旋翼稳定自转下滑时，桨叶处于不同方位，空气动力对自转转速的影

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问题单项选择题

旋翼稳定自转下滑时，桨叶处于不同方位，空气动力对自转转速的影响是（）.

A.90°方位增大转速

B.180°方位减小转速

C.270°方位增大转速，90°方位减小转速

答案

参考答案：C

填空题

根据句意及首字母（或汉语）提示完成单词

1. Jiang Lei is a g from Peking University.

2.Teachers are s to know a lot and care for the students.

3. I put the letter into the e and then had it mailed.

4. I will tell you a piece of d news that we didn't get the first prize.

5. After he made a mistake, Jim got very (紧张的) .

6. Some students from poor v in China often don't have enough money for college education.

7. We had seven subjects this s .

8. Scott is a h student. He always studies hard.

9. I'm sorry to (打扰）you. Can you lend me your pen?

10. The students didn't have classes last night. They stayed in the (宿舍).

单项选择题

肺炎球菌肺炎X线表现为（）

A.充血期可见病变部位的密度均匀影

B.肺实变期呈叶、段状密度均匀影

C.消散期阴影密度逐渐升高

D.多数阴影需6周才完全吸收

E.肺纹理增粗、增深