下列研究中研究者不能人为设置研究因素的是() A.动物实验 B.临床试验 C.社区干

题型:单项选择题 A1型题

问题:

下列研究中研究者不能人为设置研究因素的是()

A.动物实验

B.临床试验

C.社区干预实验

D.半试验性研究

E.以上都不是

考点:公卫执业助理医师卫生统计学卫生统计学题库
题型:单项选择题 A1型题

关于青霉素结合蛋白(PBPs)的描述丕正确的是

A.某些细菌细胞膜具有PBPs
B.当PBPs谱型发生改变则对β-内酰胺类抗生素产生抗药性
C.当诱导产生新的PBPs时,则β-内酰胺类抗生素抗菌作用增强
D.β-内酰胺抗生素与PBPs结合导致细菌变形死亡
E.PBPs有多种类型

题型:单项选择题 A1型题

某校高中生共有900人,其中高一年级300人,高二年级200人,高三年级400人,现采取分层抽样抽取容量为45的样本,那么高一、高二、高三各年级抽取的人数分别为________.

题型:单项选择题 A1型题

A

Once there was a man who liked to eat mangoes. One day he decided to get the sweetest mango from the very top of the tree. Mangoes which are exposed to the sun the most are the sweetest.

So he climbed up to the top, where the branches were thin. He managed to pick up a few sweet reddish fruits, but, in an attempt to climb down, he slipped and started falling towards the ground. Fortunately, he caught the branch as he was falling and remained helplessly hanging on the tree. Then he started to call nearby villagers for help. They immediately came with a ladder and sticks, but could do little to help him.

Then after some time one calm and thoughtful person arrived — a well-known sage (a wise person) who lived in a simple hut nearby. People were very curious to see what he would do, as he was famous in solving many people’s problems in the area and sometimes very complicated ones.

He was silent for a minute and then picked up a stone and threw it at the hanging man.

Everybody was surprised. The hanging mango lover started to shout: “What are you doing?! Are you crazy? Do you want me to break my neck?” The sage was silent. Then he took another stone and threw it at the man. The man was very angry: “If I could just come down, I would show you!”

That’s what everybody wanted. Then he was coming down. But how? Now everybody was tense about what would happen next! Some wanted to blame the sage, but they didn’t. The sage picked another stone and threw it again at the man, even more forcefully. Now the man on the tree was even more angry and developed a great determination to come down and take revenge (复仇).

He then used all his skill and strength and somehow reached the branches which were safe to start going down. And he made it! Everybody was amazed.

However, the rescued man found the sage gone. He stood there, realizing that the man really saved him because he induced (引诱) him to try his best and save himself.

“I should be thankful and not angry.”

小题1:From the story we know that the sweetest mango must be the one ______.

A.on the very top of a tree

B.hidden in the middle of a tree

C.on the tree for the longest time

D.exposed to sunlight less often小题2:What happened after he had picked a few sweet reddish mangoes?

A.He slipped and fell to the ground suddenly.

B.He was climbing down quickly but carefully.

C.He remained hanging helplessly on the tree.

D.He shouted loudly for help but no one helped.小题3:How did the man feel when the sage hit him with a stone?

A.He was nervous.

B.He kept silent.

C.He felt surprised.

D.He was angry.小题4:What do you think motivated (caused) the man to climb down?

A.Courage.

B.Revenge.

C.Carefulness.

D.Assistance.小题5: What does the story imply?

A.Anger saves one’s life.

B.Wisdom does count (很重要).

C.Skill and strength count.

D.Anger is the biggest enemy.

题型:单项选择题 A1型题

下列各组器件中,选项()使常用于光度计中获得单一波长的单色器。

A.碘钨灯和稳压器

B.透镜和棱镜

C.透镜和狭缝

D.光栅和狭缝

题型:单项选择题 A1型题

外国投资者专用外汇账户(费用类)的最高限额为()万美元或经批准立项的投资总额的5%。

A、5

B、10

C、15

D、20

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