单项选择题

This mathematic problem was so difficult that no student and no teacher ______ able to solve it.

A．were
B．is
C．was
D．are
<上一题 目录 下一题>
热门 试题

单项选择题
He ______ a good knowledge of English by careful study.
A．gained
B．obtained
C．earned
D．acquired
单项选择题
______ luck would have it, we arrived in time to catch the 8:00 o'clock flight to Madrid.
A．Which
B．As
C．Before
D．Because
相关试题