问题

_____________ ,they went home,________________.
A:Their workhad been finished singing and laughing
B:They hadfinished their work sang and laughed
C:Their workfinished singing and laughing
D:after theirwork finished singing and laughing
B:They hadfinished their work sang and laughed
C:Their workfinished singing and laughing
D:after theirwork finished singing and laughing
正确答案是: