—Have we        water?

—Yes,       . We’d better get some.

A．run out of; we have run it out

B．run out of ; our water has run out

C．run out of; our water has been run out

D．run out; our water has run out

下列叙述正确的是（）

A.纯合子测交后代都是纯合子

B.纯合子自交后代都是纯合子

C.杂合子自交后代都是杂合子

D.杂合子测交后代都是杂合子