单项选择题

In the experiment we kept a watchful eye ______ the subtle changes and recorded every detail.

A．for
B．at
C．on
D．to
<上一题 目录 下一题>
热门 试题

单项选择题
For nearly two hours I waited to buy a ticket for the con cert, only ______ that all tickets had been sold out.
A．being told
B．I was told
C．to be told
D．was told
单项选择题
It's harmful to one's health to ______ smoking and drinking.
A．take on
B．take to
C．take in
D．take off
相关试题