情态动词后不可以接动词不定式。只能跟动词原形。

▲情态动词后必须接动词原形，不能接带to不定式或动名词等。如：

我们应当学讲流利正确的英语。

误：We must to learn to speak English fluently and correctly.

误：We must learning to speak English fluently and correctly.

正：We must learn to speak English fluently and correctly.