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【单选题】
下列选项中对关键词表述准确的是A.
关键词与表达主题有关,但其意义很小
B.
出现频率较高的词就是关键词
C.
出现在题名、摘要、层次标题和正文重要段落的词就是关键词
D.
关键词以名词为主,包括人物、时间、人物所属领域、事件所属领域等
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参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【简答题】简述胎盘的组成、血液循环及功能。
【单选题】Keith doesn't seem to be his ______ self these days and we should pay more attention to him.
A.
ordinary
B.
common
C.
usual
D.
average
【简答题】简述胎盘屏障的组成和功能。
【单选题】Because we know more about material than ______ our ancestor, we should be able to select better ones.
A.
do
B.
know
C.
knew
D.
did
【简答题】简述胎盘的结构及胎盘功能
【单选题】听力原文：W: I think we should do more to expand our business still further. M: No, to go back to what, I was saying earlier, we really need to think again before making the decision. Q: What does the man ...
A.
The woman is entirely wrong.
B.
He is doubtful about it.
C.
The decision should be made as soon as possible.
D.
He approves of it.
【简答题】I think we should be trying to encourage more sort of(绿色交通).
【单选题】关于胎盘功能错误的为
A.
供给营养物质及排泄作用
B.
能替代胎儿呼吸功能
C.
IgG可通过胎盘使胎儿获得抗体
D.
能防御细菌、病毒及药物通过
E.
能合成激素和酶
【简答题】请简述胎盘都有哪些功能?
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