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问题 单项选择题

在RC正弦波振荡器中，一般要加入负反馈支路，其主要目的是（）。

A.改善零点漂移所产生的影响

B.保证相应平衡条件得到满足

C.提高稳定性，改善输出波形

D.稳定静态工作点

答案

参考答案：C

完形填空

第Ⅱ卷（共35分）
第四部分：写作部分（共2节）
第一节 对话填空。阅读下面对话，掌握其大意，并根据所给首字母的提示，在标有题号的右边横线上写出一个英语单词的完整、正确形式，使对话通顺。
W: What do you hope to do after graduating?
M: I’d like to go into management. I’ve (76)a_______ for several jobs
already. How about you?
W: After I finish (77)u_______, I have to do some more studies to pass
exams to become a lawyer. I think I’ve got a good chance of passing.
There’s a possibility of (78)g_______ a job with a firm in London,
provided that I do well.
M: We both have to (79)o_______ many difficulties if we are to achieve
our ambitions.
W: If life were easy, then we would achieve our ambition (80)q_______
and then get bored.
M: Unfortunately, some people are going to(81)w_______ hard yet not succeed.
W: You can’t achieve something that’s totally unrealistic.
That’s (82)w_______ ambition needs to be realistic.
M: As long as you plan carefully, most things are possible. It’s always
good to have a backup plan in (83)c       things go wrong.
W: I think it’s important to be successful in a field you are truly
(84)i_______ in, not something that other people force you to do.
M: My father wanted me to become a doctor, but I knew it would be
impossible for me.
W: I hope my (85)p_______ don’t try to interfere in my choice of career.
 
(76) ___________
(77) ___________
(78) ___________
(79) ___________
(80) ___________
(81) ___________
(82) ___________
(83) ___________
(84) ___________
(85) ___________
 
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单项选择题

下面各项不正确的是（）

A.乙型肝炎常可见到家庭聚集现象

B.丙型肝炎慢性化高

C.甲型肝炎多见于儿童

D.乙型肝炎，丙型肝炎可重叠丁型肝炎感染

E.晚期妊娠妇女戊型肝炎病死率高
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