NA是表示物镜的()A.数值孔径 B.分辨率 C.景深 D.孔径光阑

题型:单项选择题

问题:

NA是表示物镜的()

A.数值孔径

B.分辨率

C.景深

D.孔径光阑

考点:物理金相试验工初级物理金相试验工初级物理金相试验工题库
题型:单项选择题

阅读理解。

    Henry works in a factory. He comes from a poor family and was in school for only four years. He has

to do the hard work but he's paid less. He likes to watch football matches very much and spends much

time on it. One evening there was a big football match on a playground. He borrowed some money from

his friend and hurried there. There were a lot of people there. And all the tickets were sold out. He was

sorry for it. He saw a pole outside the playground and climbed up the pole quickly. A policeman came and

said, "It's dangerous to stay on it! Come down!" "Wait a minute, please!" Henry said and immediately the

policeman heard the cheers (欢呼) in the playground and asked in a hurry, "Which team has scored a goal

(进球)?" "Ours!" "Wonderful! You can stay there. But be careful!" the policeman said happily and left. A

few minutes before the match was over, he came back again and asked, "Who's won?" "Theirs, three to

two." "Come down," the policeman said angrily. "Such a match isn't worth watching!" Henry had to come

down. But soon they heard cheers again. The policeman said in a hurry, "Climb up quickly and see who's

scored a goal!"

1. Henry isn't well paid because ______. [ ]

A. he doesn't work hard

B. he works in a poor factory

C. he didn't learn much when young

D. he isn't interested in his work

2. Henry stayed on the pole because ______. [ ]

A. he could see the match clearly there

B. he didn't buy a ticket for the match

C. he didn't want to buy a ticket

D. he had no money for a ticket

3. Why did the policeman soon change his mind? [ ]

A. Because it was safe on the pole.

B. Because he was also interested in the match.

C. Because Henry didn't pay for the match.

D. Because Henry was a funny man.

4. What made the policeman angry? [ ]

A. Henry's not understanding his warning

B. Henry's refusing to tell the score

C. Henry's watching the match for free

D. Their team's losing the match

5. We can infer (推测) from the passage that ______. [ ]

A. Henry used to watch football matches for free

B. the policeman would punish Henry

C. both Henry and the policeman are superfans

D. the policeman used to watch football matches for nothing

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患儿,女,16岁,因上呼吸道感染,痰液黏稠,医嘱给予超声雾化吸入。

超声雾化吸入的主要优点是()

A.雾粒直径在25μm左右

B.雾量的大小固定,便于使用

C.气雾可直接到达终末支气管

D.病人容易接受

E.减少了药物的副作用

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Though this has been written _____ the agreement, it is not protected _____ law.

   

A.by; in

B.in; with

C.in; by

D.by; with

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下列哪项不是引起围手术期低血压的原因()

A.血容量不足

B.二氧化碳蓄积

C.心律失常

D.过敏反应

E.麻醉效果

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一般而言,Internet防火墙建立在一个网络的何处 ( )

A.内部子网之间传送信息的中枢处

B.每个子网的内部

C.内部网络与外部网络的交叉点

D.部分内部网络与外部网络的结合处

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