单项选择题

The experts worked very hard to keep up______the latest development in their own fields.
A．with
B．from
C．on
D．by

A.
A．with
B．from
C．on
D．by

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单项选择题

I asked her to be quiet. I______to hear what the teacher was saying.
A．tried
B．was trying
C．would try
D．should try

A.
A．tried
B．was
B.would
C.should

单项选择题

提出“勾三股四玄五”的勾股定理的著作是( )。

A.《周髀算经》
B．《甘石星经》
C．《洪范》
D．《周易》