问题

Before a problem can be solved, it must be obvious _____ the problem itself is. [ ]

A: what
B: that
C: which
D: why

正确答案是：

同类题型

He _____ football regularly for many years when he was young

Everything went on as usual ______ nothing had happened

If you don’t study English all thetime, you’ll have a difficult time ____ it in the future.

下列各句中加点的成语的使用，正确的一项是（3分）

you may have finished unit one _____ , you can go on to unit two