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【单选题】
生产机械运动部件在正、反两个方向运动时,一般要求电动机能实现( )控制。A.
正转
B.
反转
C.
正、反转
D.
制动
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知识点：
皮皮学刷刷变学霸
举一反三
【单选题】Task 2 You will hear eight short conversations. After each conversation, you should decide on the best answer from the four choices marked A, B, C and D.
A.
Go to see the later show.
B.
Wait for ten minutes.
C.
Come back in ten minutes.
D.
Never go to the movies.
【单选题】关于蛋白质分子三级结构的描述，正确的是
A.
天然蛋白质分子均有这种结构
B.
具有三级结构的多肽链都具有生物学活性
C.
三级结构的稳定性主要由肽键维系
D.
亲水基团多聚集在三级结构的内部
E.
决定其空间结构的因素是辅基
【单选题】What can we infer from the last paragraph of the article?
A.
The severely fat patients are threatened with potential illness.
B.
The diet-pills have been sold to all comers without discrimination.
C.
The diet-pills should not have been hailed as miraculous cures and then discarded as dangerous drugs.
D.
The diet-pills were intended to a short-term cure for the very fat.
【单选题】Task 2 You will hear eight short conversations. After each conversation, you should decide on the best answer from the four choices marked A, B, C and D.
A.
1,000 yuan.
B.
1,500 yuan.
C.
1,200 yuan.
D.
2,000 yuan.
【单选题】Task 2 You will hear eight short conversations. After each conversation, you should decide on the best answer from the four choices marked A, B, C and D.
A.
The children.
B.
A film.
C.
The guests.
D.
A broken TV.
【单选题】关于蛋白质分子三级结构的描述，错误的是( )
A.
天然蛋白质分子均有这种结构
B.
具有三级结构的多肽链都具有生物学活性
C.
三级结构的稳定性主要是次级键维持
D.
亲水基团聚集在三级结构的表面
E.
决定盘曲折叠的因素是氨基酸残基
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