___difficult it was,they managed to solve the problem on time.

问题描述:

___difficult it was,they managed to solve the problem on time.
为什么选however而不选no matter

如果用no matter,后面还要加how,就是no matter how difficult it was不管有多么困难,how是修饰difficult的,所以不能少.
换句话说,no matter how=however
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