问题 单项选择题

心房收缩期在心血管生理上的意义()。

A.心房的血液因心房收缩,最终全部被充盈到左心室

B.左心房收缩引起左心室收缩

C.心房收缩期引起心室的快速充盈

D.心房收缩是舒张期的开始

E.心房收缩期是左心室射血的终结

答案

参考答案:A

阅读理解

阅读理解.

     The dinosaurs once lived happily on the earth. But 65 million years ago, they suddenly died out. What

happened to them?

     Scientists think that a change in temperature may be to blame. They have come up with lots of ideas

to explain the end of the dinosaurs. 

     The most famous one is the minor planet (小行星) idea. Let's go back to that day 65 million years ago

to see what happened. Everything was OK before a large minor planet suddenly hit the earth. What a

terrible hit! It caused big fires, storms, acid rain (酸雨), and even earthquakes and volcano eruptions. The

hit produced a lot of dust, which flew up into the air and blocked the sun for months. The earth became

very cold without sunlight. The plants died first. Then the grass eating animals died of hunger. Then the

meat eating animals could not find food, either. They began to eat each other, but after a while they died

out, too. The dinosaurs, either plant-eaters or meat-eaters, did not live through the disaster. What a sad

story !

     In April, a British scientist thought of a new idea about the death of the dinosaurs.

     He thinks that after the minor planet hit the earth, the temperature change left more dinosaur

boys than girls! Without enough female dinosaurs to hatch the eggs, the dinosaur population became

smaller and smaller.

1.                  may be the main reason for the dinosaurs dying out according to scientists.

A. Big fires

B. Earthquakes

C. Acid rain

D. Temperature change

2. The passage mentioned                  ideas that the scientists came up with about the end of the dinosaurs.

A. two                        

B. three

C. four                        

D. five

3. The underlined expression "volcano eruptions" probably is                   .

A.the name of a minor plane

B. one kind of dinosaurs

C. one kind of disaster

D. the name of an earthquake

4. The earth became cold because                    .

A. the sun refused to rise

B. the dust kept the sunlight away

C. there's too much rain

D. there are too many dinosaurs

5. This passage may be found in                    .

A. a science fiction      

B. a story book

C. a dictionary          

D. a science magazine

填空题