问题 问答题

如图所示是我国东海大桥的一部分.东海大桥始于上海,跨越杭州湾北部海域,直达浙江小洋山岛,是世界现有30多座跨海大桥中最长的一座,总长达33km.一辆汽车匀速通过大桥的时间约为0.5h,则这辆汽车的平均速度是多少km/h?如果汽车的速度为50km/h,则通过大桥的时间要用多少小时?

答案

(1)s=33km,t1=0.5h

汽车的速度是v1=

s
t1
=
33km
0.5h
=66km/h

(2)s=33km,v2=50km/h

∵v=

s
t

∴汽车过桥需要的时间t2=

s
t2
=
33km
50km/h
=0.66h.

答:则这辆汽车的平均速度是66km/h;如果汽车的速度为50km/h,则通过大桥的时间要用0.66h.

阅读理解

阅读理解。

     Illegal removal of coral (珊瑚) along Sri Lanka's coastline increased the amount of destruction on the

island by last December's tsunami, say researchers.

     Harindra Fernando, a fluid dynamicist (力学家) at Arizona State University in Tempe, made the connection

after a visit to his native Sri Lanka earlier this year. While serving as a scientific expert and translator for a

BBC-documentary team, he chatted with locals who said they saw the tsunami turn sideways when it hit

coral-which would have made it less powerful than in coral-free areas. Fernando linked this to trucks he had

seen last year carrying piles of coral away from the sea.

     Using the eyewitness reports, estimates (估算) of wave heights, and a series of divers to check the

presence or absence of corals, Fernando and his colleagues produced a map of coral gaps and wave flooding

along Sri Lanka's southwest coast.

     The tsunami reached significantly farther inland through the gaps: in one instance, the water traveled 1.5

kilometres long and knocked a passenger train off its tracks, killing 1,700. But only a few kilometers away,

where the coral was still undamaged, the wave travelled just 50 metres inland and caused no deaths.

     There is a similar phenomenon. In Nicaragua in 1992, a tsunami poured through a break in the coral reef

made to let boats through. "Within this passage, water went one kilometre inland," says Fernando. "But

nearby, where the coral was undamaged, there were still beach umbrellas standing."

     In Sri Lanka, coral is illegally mined to provide souvenirs for tourists, or to be used in house paint. Coral

harvesters sometimes blow it up with dynamite (炸药) in order to collect fish at the same time. Often, the

reefs in the best shape are those in front of hotels, as the hotel owners maintain them for the tourists.

Fernando hopes that his findings will encourage the Sri Lankan government to enforce (实施) its laws against

coral mining.

1. Harindra Fernando did all the following EXCEPT ______. [ ]

A. serving as a translator for a BBC-documentary team

B. helping the Sri Lankan government enforce its laws against coral mining

C. producing a map of coral gaps along Sri Lanka's southwest coast

D. linking the coral removal with the destruction of Tsunami

2. The main idea of Paragraph 5 is that ______. [ ]

A. undamaged coral can greatly decrease tsunami damage

B. coral-free area is a danger to passenger trains

C. in general, water travels 30 times farther inland in a coral-free area

D. it is urgent to enforce laws against coral mining

3. Which of the following may NOT be the cause of coral gaps? [ ]

A. Boat passages.

B. Tourists' sightseeing.

C. Fish collecting.

D. Tourists' souvenirs.

4. Which of the following would be the best title for the passage?[ ]

A. Harindra Fernando, a Great Environment Protector

B. Stop Using Coral as Souvenirs

C. Coral Cried "Help! Help!"

D. Coral Mining Enhanced (加剧) Tsunami Damage

问答题 简答题