fail to的同义替换：not succeed in doing sth；不成功，未能

fail to：v.未能;使…失望

例句：But we did not succeed in our objective.

但是我们的目的没有达到。

Try as he might, he did not succeed in it.

他虽千方百计，但仍没有成功。

I did not succeed in my first lecture.

我第一次讲课不成功。

Yet the Japanese did not succeed in annihilating the forces opposing them.

尽管如此，日本军队仍然消灭不了抗日武装。