you'd better find out___they are up to before opening the door.A.what B.that C.as D.wherethey are up 选什么?

来源：学生作业帮助网编辑：作业帮时间：2024/05/16 14:31:55

you'd better find out___they are up to before opening the door.A.what B.that C.as D.wherethey are up 选什么?
you'd better find out___they are up to before opening the door.
A.what B.that C.as D.where
they are up 选什么?

you'd better find out___they are up to before opening the door.A.what B.that C.as D.wherethey are up 选什么?
选A
what they are up to 他们在做什么