例： it's so nice to hear from her ＿＿，we last met more t thirty years ago.
A. what's more
B. That's to say
C. other words
D. Believe it or not
1. -Hi, I'm Peter. Are you new here? I hav't s you around？
-Hello, Peter. I'm Bob. I just＿＿on Monday.
B. have started
D. had started
2. ＿＿we don't stop ate ge, y als d pts the world will be gone.【21教育】
3. ＿＿along the old Silk Road is terestg d rewarg experce
C. Havg traveled
4. Sus had quit her well-paid job d ＿＿as a volunteer the neighborhood. I visited her last year21*教*育*名*师
A. is worg
B. was worg
C. has worked
D. had worked
5. She d her ily bicycle to work, helps t keep fit
6. Durg the Mid-Autu Festival, ily bers oft gather together＿＿a meal, ire the moon d joy moon cakes.
B. to share
C. havg shared
7. a's high-speed railways from 9,000 to 25,000 kilometers the pastfew years.
A. are grog
B. have grown
C. will grow
D. had grown
8. y unsafe situation, sply＿＿the button d a highly-tred t will get you the help you need.
B. to press
9. A rescue worker risked his life savg two tourists who＿＿ the mounts for two days.
A. are trappg
B. have trapped
C. were trappg
D. had trapped
10. Orary soap, ＿＿correctly, deal with bacteria effectively.
B. to use
11. Without his support, we wou't be＿＿we are no.
40. Why do people come to SAC?
A. To experce advtures.
B. To look for jobs aviation.
C. To get a degree eerg.
D. To learn more about e.
41. To earn a Space Exploration badge, a tree needs to .
A. fly to space.
B. get Aviation badge first.
C. study the prciples of flight.
D. build d fire model rockets.
42. What is the most portt for trees?
B. T spirit.
C. Task png.
D. Survival skills.
Hus produce more t 300 million tons of plastic every year. ost half of that ds up dfills(垃圾填埋场)， d up to 12 million tons pollute the os. qSo far there is no effective way to get rid of it, but a new study suggests swer may lie the stomachs of some hungry worms.
Researchers Sp d d rtly found that the worms of the greater wax moth break down polyethye, which accounts for 40% of plastics. The t left 100 wax worms on a coercial polyethye shoppg bag for 12 hours, d the worms consumed d broke down about 92 milligrs, or ost 3% of it. To confirm that the worms' cheg alone was not responsible for the polyethye breakdown, the
researchers made some worms to paste(糊状物) d applied it to plastic s. 14 hours later the s had lost 13% of their mass--appartly bro down by zymes(酶)from the worms' stomachs. Their gs were published Currt Biology 2017.
Federica Bertoi, co-author of the study, says the worms' ability to break down their everyday food-beeswax--also allows t to break down plastic "Wax is a complex mixture, but the basic bond polyethye, the carbon-carbon bond, is there
as well, "she exps. "The wax worm evolved a method or syst to break this bond. "
nifer Debruyn, a microbiologist at the University of Tnessee, who was not volved the study, says it is not surprisg that such worms break down polyethye. But compared with previous studies, she ds the speed of brg down this one excitg. The next step, DeBruyn says, will be to tify the cause of the breakdown. Is it zyme produced by the worm itself or by its gut microbes(肠道微生物)?
Bertoi agrees d hopes her t's gs might one day help ploy the zyme to break down plastics dfills. But she expects usg the ical some d of dustrial processot sply "millions of worms thrown on top of the plastic."
43. What we learn about the worms the study?
A. They take plastics as their everyday food.
B. They are newly evolved creatures.
C. They consume plastics.
D. They d up dfills.
44. Accorg to nifer DeBruyn, the next step of the study is to .
A. tify other s of the breakdown
B. d out the source of the zyme
C. confirm the research gs
D. crease the breakdown speed
45. It be ferred from the last paragraph that the ical might .
A. help to raise worms
B. help make plastic bags
C. be used to the os
D. be produced factories future
46. What is the purpose of the passage?
A. To exp a study method on worms.
B. To troduce the diet of a special worm.
C. To prest a way to break down plastics.
D. To propose new s to keep ecoce.
Preparg Cities for Robot Cars
The possibility of self-drivg robot cars has oft sed like a futurist's dr, years away from materializg the real world. Well, the future is appartly now. The California Departt of Motor Vehicles givg permits April for compies to test truly self-drivg cars on public roads. The state also cleared the way for compies to sell or rt out self-drivg cars, d for compies to operate driverless taxi services. California, it should be noted, isn't g the way here. Compies have testg their vehicles cities across the country. It's hard to predict 【21・世纪・教育・网】
driverless cars will be everywhere on our roads. But however long it takes, the tology has the pottial to ge our trsportation systs d our cities, for better or for worse, depg on how the trsformation is regulated.
While much of the debate so far has focused on the safety of driverless cars(d rightfully so), policymakers also should be tg about how self-drivg vehicles help reduce traffic s, cut issions(排放) d offer more convt, affordable
mobility options. The arrival of driverless vehicles is a ce to make sure that those vehicles are virontally frdly d more shared.
Do we t to copy- or ev wors- the traffic of today with driverless cars? e a future where most adults own dividual self-drivg vehicles. They tolerate long, slow journeys to d from work on packed highways because they work, tert tselves or sleep on the ride, which courages ur spread. They take their driverless car to appott d set the pty vehicle to circle the bug to avoid payg for parg. stead of g a few blocks to pick up a child or the dry g, they sd the self-drivg ibus. The convce ev leads fewer people to take public trsport unwelcome side effect researchers have already found ride- g(叫车) services.
A study from the University of California at Davis suggested that repg petrol-powered private cars worldwide with electric, self-drivg d shared systs could reduce carbon issions from trsportation 80% d cut the cost of trsportation frastructure
(基础设施) d operations40%by2050. Fewer issions d cheaper travel sound pretty appg. The first coercially available driverless cars will ost certly be fielded by rg services, considerg the cost of self-drivg tology as well as liability d tce issues(责任与维护问题).But driverless car ownership could crease as the prices drop d more people become comfortable with the tology.
Policymakers should start tg now about how to make sure the appearce of driverless vehicles doesn't extd the worst aspects of the car-controlled trsportation syst we have today. The cog tological advt prests a ce for cities d states to develop trsportation systs desed to move more people，d
more affordably. The car of the future is cog. We just have to p for it.
47. Accorg to the author，atttion should be paid to how driverless cars __________.
A. help deal with trsportation-related pros
B. provide better services to customers
C. cause age to our viront
D. make some people lose jobs
48. As for driverless cars，what is the author's major concern？
B. Side effects.
49. What does the undered word "fielded" Paragraph 4 probably ？
50. What is the author's attitude to the future of self-drivg cars？
Why Do We Get gry？
ger ss sple we are g it， but the causes of ger are various. og these causes make us exe our behavior，d correct bad habits. The reasons we get gry are triggerg（触发）evts，personality traits（特征），d our assesst of situations. 51
Triggerg evts for ger are so y that to describe t all would take hundreds of pages. However, here are some exples: g cut off traffic, a e approg, experg physical p, d much more._52 The reason why someone is triggered by sometg d others are not is oft due to one's personal history d psychological traitsjy*com
Each person. no matter who they are, has psychological ces. People who have personality traits that conncct with competitivess d low upset tolerce are much more likely to get gry. 53 Also, sometes prger does not have to do with a lastg condition, but rather a tporary state before a triggerg evt has occurred.
____54 Sometes ev route occurrces become sources of prger, or ger itself. Sometes orce d negative (消极的)outlooks on situations create ger.
____55 However, ger easily turn viot, d it is best to ow the reasons for ger to appear order to prevt its presce. With these reasons d, we evaluate our level of ger throughout the day d prevt cases of outbursts by comprg the reasons for our gs.
A. Our attitude d viewpot on situations create ger wit us as well.
B. But some types of situations help us to get rid of the occurrce of ger.
C. ger is rarely looked upon as a eficial character trait, d is usually advised to reduce it.
D. ger is a particularly strong g d maybe people tk that they have reasons to feel gry.
E. Havg these personality traits plies the prger state, where ger is the background of your d.
F. Understg these reasons will control our own ger if we are g to evaluate ourselves with a critical eye.
G. Not everyone acts the se response to evts, d that is why what triggers one person may or may not trigger other.