题目内容

什么叫并联杠杆系？什么叫串联杠杆系？它们各有什么用途？

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They have to stay with us _______ the time being because they have not found a place yet。

A. during
B. in
C. for
D. since

Frank couldn‘t help _______ his wife that he was worried about losing his job。

A. tell
B. to tell
C. telling
D. expect tell

Jane came _______ because her car has broken down。

A. by feet
B. on feet
C. with foot
D. on foot

The President was among the first to congratulate the scientist _______ his new discovery。

A. at
B. in
C. about
D. on