Listen！Who________behind the tree？
A．sings
B．sing
C．singing
D．is singing
My brother left school in 2005，and since then he________in Beijing．
A．lives
B．lived
C．will live
D．has lived
We didn’t start our discussion________everybody arrived．
A．since
B．if
C．while
D．until
我一再警告你不要那样做。
I’ve warned you________ ________ ________ ________not to do that．
毕业后他就独立生活了。
After graduation，he lives________ ________ ________．
据我所知，我们下星期一要进行一次测试。
As far as I know，we will________ ________ ________next Monday．
