Geophysicist Dr. Andrea Donnellan of NASA's Jet Propulsion Laboratory,Pasadena, Calif., remembers the morning of January 17, 1994, like few others.Like millions of other Southern California residents, she was shaken from her sleep in her normally tranquil foothill community home as a large earthquake caused a mountain, located just 30 miles away, to grow nearly 15 inches higher, all in a matter of seconds. "Large earthquakes are always disconcerting," she said. "Being a geophysicistI was immediately interested in how large the earthquake was and where it hadoccurred." Less than two months before that fateful day, Donnellan and colleagues fromthe Massachusetts Institute of Technology had published a landmark paper inthe journal Nature on ground distortion north of LA's San Fernando Valley. Sixyears of relatively sparse data from a fledgling network of Global PositioningSystem (GPS) deformation monitors,that had been developed and installedaround Southern California by scientists at JPL and other organizations, haddetected that Earth's crust was being squeezed closed across the VenturaBasin. The data showed the area's faults were accumulating strain, and they gave the scientists clear indications of the style and relative size of anearthquake that might strike there, even though the faults there do not allbreak the surface. They placed no time frame on when such a temblor mightoccur, however. "The Northridge GPS measurements solidified in many scientists" minds how valuable data from space-based instruments could be for collecting precise measurements of Earth's crustal movements," said Donnellan. "We knew thatsomething was up because an earthquake had not occurred there historically andyet a large amount of strain needing to be released had accumulated. After the earthquake, additional GPS data made it possible to rapidly and uniquely determine where the fault ruptured and to measure how the earthquake had deformed Earth's surface." In the decade since Northridge, a high-tech, GPS￾based ground deformationnetwork was installed within Southern California. Called the Southern California Integrated GPS Network, it provides a continuous measurement ofground deformation at 250 locations with a precision of a few millimeters,measuring the slow buildup of deformation along faults. In addition,advancesin satellite-based radar Interferometric Synthetic Aperture Radar (InSAR) andlidar are now used in combination with the GPS measurements to provide imagesof ground deformation for the entire Southern California earthquake region.These new technologies, coupled with powerful new computer modeling capabilities, have _revitalized_ research in understanding earthquakes and earthquake processes. The new technologies will substantially refine earthquake hazard maps.

A.large earthquakes are usually unpredictable

B.Dr. Donnellan is bewildered by large earthquakes

C.large earthquakes always cause mountain moves

D.geophysicists should take more interest in large earthquakes

A.Earth's crust was destroyed across the Ventura Basin.

B.The faults in Massachusetts broke Earth's surface.

C.There were vague signs of the style of an earthquake recently.

D.Data indicated faults were accumulating strain in the Ventura Basin.

A.define the faults of Earth's crust

B.forecast the potential earthquake

C.provide valuable data for scientists

D.detect the eruption of a volcano

A.study the structure and evolution of North American continent

B.continuously provide information of Earth's surface deformation

C.control earthquakes and volcanic eruptions

D.substantially refine the images of Earth

A.spread the knowledge of

B.enriched the idea of

C.caused to return to

D.gave vigor to

I have three kids under 10 who don't expect—or even want-to play with me. It took some practice, but over time, we've all learned we're better off doing our own thing: the kids, without stodgy parental interference, and my husbandand I, unhooked from the assumption that we have to play to be present.It wasn't always this way. As a toddler, if my first child wasn't digging in the trash or chewing on the couch cushions, he was rampaging through the housewith an imaginary weapon. He never listened. He tried to run into traffic. The constant wrangling and vigilance were so exhausting that my husband and Ididn't have the energy to play the way my son preferred. Instead, I said noand stopped all day long, and when my scolding seeped into the playing, I feltguilty and frustrated.I was a terrible playmate, a tired mother who didlittle beyond obstructing. But when my son was about 3, I realized his fictive worlds were vivid enough to continue without me. All he needed, at first, was a listener. After awhile, he would head into his bedroom, alone, to transform it into the placethat lived in his mind. It was freedom—for all of us. Thus began an experiment with expectation.Little by little, my husband and I would stretch the timeour son could safely play by himself. My daughter was born a year after that. She is shy and moody,and she has beencontent to play on her own since she could crawl. I've never met a more self-possessed child—she used to tell me when she needed a nap. She has never likedthe sorts of games her brother prefers, and play between them has always beena negotiation. The games they've created combine his love of fantasy and dramawith her need for realism; when they set up their pretend yak farm withpillows and stuffed animals, she enjoys an imagined sunset, while her brother worries about predators who have yet to grace this earthly plane. In the past, if they couldn't agree on a game's direction, I would try tohelp, only to make it worse. When Mom is there to listen, they turn defensiveand mean; when I say, "Figure it out," they do. I know I'm lucky they haveeach other to play with,and so I've taught myself to hold back. I tell myselfthey're learning about compromise and boundaries. I have a bad temper. I canbe critical. And I don't like to play, especially pretend, or anything with dolls or figures, or any games that ask me to hide or wield a Nerf gun. Mymotto is "Moms don't play." Our third child joined the family with this systemin place, and he is, as most third children are, remarkably independent.

A.shows that the mom is lucky to have two kids to play with each other

B.makes the kids get rid of the idea of having mom to accompany them

C.tells the kids that moms are occupied with housework

D.indicates that moms are not good game players

A.Parents are often good playmates of their kids.

B.Parents may give their kids more freedom to play.

C.Caring parents are usually problem solvers.

D.Strict parents will bring up independent kids.

A.She is tolerant and considerate.

B.She is violent and moody.

C.She is blue and frustrated.

D.She is impatient and critical.

A.a child's imagination may help him play by himself

B.parents should let their child play safely outside

C.a child's fictive worlds need his mother

D.parents should be the first listeners

A.She is obedient and quiet.

B.She lives in her own world.

C.She has her own favor in games.

D.She likes fantasy when playing games.

What to do after retirement? That's the question most retirees ask themselves.Since my retirement two years ago, I too have been trying to find an answer tothe question, among other things, by observing what other retirees are doing to adjust to their new daily routine. Since Chinese people have strong family bonds, many retirees take care oftheir grandchildren. Although fewer and fewer parents and their grownup children live together in cities, the parents

still consider it their duty totake care of their grandchildren. In rural areas,on the other hand, manypeople leave their children in the care of their elderly parents and move tocities to get better-paying jobs. As exhausting as looking after a child is, many grandparents seem to enjoy it.In the elevator of my apartment building, I once overheard an old couple complaining that their

daughter-in-law's parents were not skilled orexperienced enough to take care of their grandson, and therefore they shouldlet them take care of the child. But a more meaningful choice would be to attend a university course for seniorcitizens. China has thousands of such colleges where subjects such asliterature, music, dancing, calligraphy, painting and handicraft are taught.According to data, more than 8 million elderly people have enrolled ingovernment-sponsored universities. For about 150 yuan, a senior citizen can enroll in a one-year course. But since the waiting list in such universitiesis long owing to too many applicants, local communities run classroomsoffering free courses to meet the needs of the elderly.However, square dancing is by far the most popular recreational activity forveterans. Senior citizens gather in parks, squares and other open spaces anytime between 6:00 am and 10:00 pm to practice and enjoy group dancing-fromwaltz to rumba and yangko to Uygur dance. Dancing helps the elderly not only to get enough physical exercise but also gives them an opportunity to chatwith their peers, which adds some color to their otherwise lonely life. Also, many retirees love traveling. They can do so freely before they reach70, because many travel agencies refuse to include people aged above 70 intour groups to avoid dealing with medical and other emergencies. In manycases, overseas tours for the elderly are booked and paid for by their grownupchildren, and about half of the outbound group travelers are senior citizens,So big is the market that many travel agencies organize chartered flights andtrains for elderly people,including those above 70.

A.a task given by their grownup children

B.a wise choice in their retiring life

C.their responsibility

D.their life goal

A.They run one-year courses for the elderly.

B.They provide diversified courses for the elderly.

C.They can hold all the elderly who want to enroll in.

D.They offer free courses to meet the needs of the elderly.

A.it is the only physical exercise they can do

B.it enables them to contribute more to the community

C.it gives them the chance to relax and make friends

D.it is the most popular recreational activity in their view

A.they can afford the expensive journey all on their own

B.they are offered well-organized trips by travel agencies

C.they are encouraged to go abroad by travel agencies

D.their grownup children organize the trip for them

A.colorful and enjoyable

B.exhausting and bitter

C.adventurous and peaceful

D.disordered and painful

City air is in a sorry state. It is dirty and hot. Outdoor pollution kills4.2m people a year, according to the World Health Organization. The relentless spread of buildings and roads turns urban areas into heat islands,discomforting residents and _exacerbating_ dangerous heatwaves, which are inany case likely to become more frequent as the planet warms. A possible answer to the twin problems of pollution and heat is trees. Their leaves may destroy at least some chemical pollutants (the question is debated)and they certainly trap airborne particulate matter, which is then washed tothe ground by rain. And trees cool things down. Besides transpiration, they provide shade. Their leaves have, after all, evolved to intercept sunlight,the motor of photosynthesis. To cool an area effectively, though, trees must be planted in quantity. In2019 researchers at the University of Wisconsin found that American citiesneed 40% tree coverage to cut urban heat back meaningfully. Unfortunately, notall cities are blessed with parks, private gardens or even ornamental street trees in sufficient numbers. And the problem is likely to get worse. One group of botanists believe they have at least a partial solution to this lack of urban vegetation. It is to plant miniature forests, ecologically engineered for rapid growth. Over the course of a career that began in the1950s their leader, Miyawaki Akira, a plant ecologist at Yokohama National University, in Japan, has developed a way to do this starting with even themost unpromising abandoned areas. And the Miyawaki method is finding increasing favor around the world. Dr. Miyawaki's insight was to deconstruct and rebuild the process of ecological succession, by which bare land develops naturally into matureforest. Usually, the first arrival is grass. Shrubs sprout later, followed by small trees and, finally, larger ones. The woodlands therefore contain different species. The Miyawaki method skips some of the early phases andjumps directly to planting the kinds of species found in a mature wood. Using a wide mix of species, not all of them trees, is important. But trees,shrubs and ground-covering herbs all coexist in natural forests, and the Miyawaki versions therefore have this variety from the start. Not only doesthat pack more greenery into a given space, it also encourages the plants to grow faster-for there are lots of positive ecological relations in a natural forest. Vines rely on trees for support. Trees give shade to shrubs. And,beneath the surface, plants' roots interact with each other, and with soilfungi, in ways that enable a nutrient exchange which is only now beginning to be understood. 

A.worsening

B.alleviating

C.mitigating

D.degrading

A.they can interrupt photosynthesis

B.they can help people to cool down

C.they can help wash particular pollutants

D.they can trap particles carried in the air

A.In order to reduce urban heat effectively, we need to plant trees in quantity.

B.In cities, parks and private gardens contribute to 40 per cent tree coverage.

C.The problem of lack of vegetation in poor countries can be changed soon.

D.The Miyawaki team is gaining increasing support around the world.

A.Trees, shrubs and vines all grow independently in the forest.

B.Plants in the forest need additional chemical fertilizers.

C.The forest first starts with big trees and then grass.

D.The forest contains a wide variety of species.

A.how ecological engineering find favor around the world

B.how Miyawaki starts his career as a gardener

C.how miniature forests can help air-condition cities

D.how bare land develops into private gardens

Q. There's a lot of talk about putting up manned orbital stations. What does this mean, concretely?

A. It is very important to have scientifics tations in space. A space telescope with a mirror slightly over six and a half feet in diameter will beplaced in orbit, and there will be more and more of these.A few years ago,our group at Saclay, in collaboration with a number of other European Laboratories, orbited a telescope that revolutionized our knowledge of gamma-ray emissions by celestial objects.

Life aboard manned space stations won't be as exciting as we might suppose. It will probably be comparable to the life people lead aboard deep-sea oil rigs.

Q. What scientific interest will these stations offer?

A. Observation is much more precise beyond the atmosphere,because the sky is darker. You see many more stars and objects that are concealed by the earth's luminescence.

Q. What objects?

A. We know pretty well how stars are born because we can observe them. Two or three new stars appear in our galaxy every year. But nearly all the galaxies were born at the same time, when the universe was constituted 15 billion years ago. No new ones are thought to exist. To observe the birth of a galaxy that happened so long ago, you have to see avery long way. At present we can go back 10 to 12 billion years. We have to goa bit farther back still, and maybe catch them in the act of birth. Distant objects are necessarily very dim, so ideal conditions are needed to observe them. Orbital stations provide such conditions.

Q. Would orbital stations be choice places from which to try to communicate with extraterrestrial intelligences?

A. Not particularly through radio communication, except on certain wave lengths that are absorbed by the atmosphere. But as points of departure forexploration they'll be very useful.

Q. How far would such exploration go?

A. In 1989 the satellite Voyager II will reach Neptune after a journey of three and a half years. In addition, five probes were sent to rendezvous with Halley's comet. So exploration of the solar system is more or less under way.We've put people on the moon, sent probes to Mars and Venus, lofted satellites near the sun (within a few tens of millions of miles), and one satellite even left the solar system a few years ago. But visiting the stars is something else again. Light takes four years to reach the nearest stars, so you can see that it would take a satellite hundreds of thousands of years.

Of course, if the earth were to become over populated, we can imagine sending families in space vessels to colonize the nearest stars. But it's their great-great-great-grand children who would finally reach those stars. And they wouldn't even know where to stop.