问题 选择题

验证酶的高效性实验成功的关键是[ ]

A.试管是否干净

B.肝脏是否新鲜

C.卫生香(或火柴梗)是否点燃

D.是否有对比实验

答案

答案:B

单项选择题
阅读理解

阅读理解

      For 170 years,members of a tiny American native tribe have lived and celebrated their traditions on a

small piece of land off the Louisiana coast called Isle de Jean Charles.They fished and they farmed,making

livings by hard work amid the bays and marshes(沼泽).But now the waters that have supported them

are threatening to overwhelm them.

      "I don't think we're going to have to have any other choice except to leave because we're getting

washed away by every storm that comes by," said Albert Naquin,chief of the BiloxiChitimacha tribe."We

have lost more and more land,and it keeps happening."

      Surrounded by the Gulf of Mexico on one side and the marsh on the other,Isle de Jean Charles sits at

the southern tip of Louisiana's rapidly disappearing wetlands,an area that is 3 to 4 miles long and about a

mile wide.The tribe has been living here since 1840.But about a football field worth of land in the region is

lost every half hour because of erosion(侵蚀),storms and rising sea water-a constant process that is

expected to worsen with climate change.

      Isle de Jean Charles has been flooded five times in the last six years,being transformed from a once

lush(繁茂的) landscape into a barren disaster zone.The floodwaters have spread large amounts of salt

across the tiny island,making it nearly impossible for much to grow any more.

      The road to their village has been flooded so often,and now only one narrow road is usable,

which is often covered by water.The fire station was closed a few years ago,and the island's church was

relocated.Now,only 25 families are left,with a "few dozen" people.A controversial $900 million system of

sea walls to save endangered communities along the Louisiana coast raised hopes here.But the final

design did not include Isle de Jean Charles because officials concluded it simply would cost too much to

protect the relatively few families that were left..

1.What would be the best title of the passage?

A. Climate change threatens an American native tribe.

B. Decreasing population of an American native tribe.

C. The survival of an American native tribe.

D. The harmful effect of climate change

2.We learn from the third paragraph that ________.

A. only a football field worth of land remains for the tribe

B. the southern tip of the wetlands is now in water

C. the tribe is losing its land at a fast speed

D. the tribe has lived here for 300 years

3.What do we know about the remaining land of Isle de Jean Charles?

A. It still remains rich and beautiful.

B. It has become unsuitable for cross to grow.

C. Most of it has become wetlands.

D. All of them has been covered by water.

4.The sea walls will fail to protect the tribe because officials think ________.

A. sea walls will be dangerous for the people living there

B. sea walls will affect the living of the creatures in the sea

C. building sea walls would cost the people living there too much money

D. it's not worthwhile building sea walls to protect the few families