单项选择题

He has not quite solved the problem yet, but he is ______ it.

A．making of
B．working on
C．clearing up
D．trying out
<上一题 目录 下一题>
热门 试题

单项选择题
______ Mary had heard that sound was she really frightened.
A．Not when
B．Not as
C．Not until
D．Until
单项选择题
Your father is seriously iii and you should ______ a doctor at once.
A．send out
B．call in
C．go into
D．leave for
相关试题