试题与答案

心肌不产生完全强直收缩是由于A.心肌是功能合胞体 B.兴奋传导有房室延搁 C.窦房结

题型:单项选择题

题目:

心肌不产生完全强直收缩是由于

A.心肌是功能合胞体

B.兴奋传导有房室延搁

C.窦房结对潜在起搏点有抑制作用

D.有效不应期特别长

E.收缩期较短

答案:

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题型:阅读理解

阅读理解。

    Skin-diving is a new sport today. This sport takes you into a wonderful new world. It is like a visit to the

moon! When you are under water, it is easy for you to climb big rocks, because you are no longer heavy.

     Here, under water, everything is blue and green. During the day, there is enough light. When fish swim

nearby, you can catch them with your hands.

     When you have tanks of air on your back, you can stay in deep water for a long time. But you must be

careful when you dive in deep water.

     To catch fish is one of the most interesting parts of this sport. Besides (而且), there are many uses for

skin-diving. You can clean ships without taking them out of the water. You can get many things from the

deep sea.

     Now you see that skin-diving is both useful and interesting.

1. Skin-diving will take you to _____. [ ]

A. the moon

B. be in danger

C. mountains

D. the deep sea

2. You can climb the big rocks under water because _____. [ ]

A. you are stronger

B. the fish nearby help you

C. you are not as heavy as on land

D. there is a lot of light

3. Under water, a skin-diver _____ in the daytimes. [ ]

A. can see everything clearly

B. can't see anything clearly

C. can see nothing

D. can see only fishes

4. With a tank of air on your back, you can _____. [ ]

A. catch fish very easily

B. stay under water for a long time

C. be in safe place

D. have more fun

5. Which of the following sentences is NOT true? [ ]

A. Skin-diving is a new sport.

B. Skin-diving is like visiting the moon.

C. The only use of skin-diving is to have more fun.

D. Skin-diving is both interesting and useful

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