they are ( )an english song 里面填sing
问题描述：
they are ( )an english song 里面填sing
里面填sing还是sing的现在分词
答
sing的现在分词,因为已经有谓语are了,一个句子只能有一个谓语动词!所以只能填现在分词!sing的现在分词是啥