_____ their homework,they went to the playground to play football

题目

_____ their homework,they went to the playground to play football
a.finished b.having finished
c.finishing d.to finish
为何选B

答案

独立主谓结构,主语是they
所以不能用被动语态,
之所以用完成时,是因为后面有描述前面行为所带来的效果,
完成了作业才可以去踢球,产生了影响.
所以选B