after可做介词也可做连词.所以 after后可加动词ing或一个句子,加句子时用作时间状语从句,主句用一般现在时,从句也用一般现在时 he plays football 是一个句子,此时after用作连词.因此play不加ing.加ing的情况如：He often watches TV after finishing his homework.