___you___out the problem ,sam?

问题描述:

___you___out the problem ,sam?
not ,yet but I'm going to
a.did,work b.are,working c.have,worked d.will work

have you worked out the problem ,sam?
not ,yet but I'm going to
a.did,work b.are,working c.have,worked d.will work
我是从事英语 的,不明可问.