could I go to a movie after I finish __ the piano.填写适当的词

问题描述:

could I go to a movie after I finish __ the piano.填写适当的词

playing.
我不知道他让你填的是什么词,但是肯定是一个动名词.也就是doing的结构.因为前面的finish只能加动名词做短语.