羊场的贮粪池和埋尸井，应位于羊舍的（）
A.上风向
B.下风向
C.中间位置
D.什么风向都可以
参考答案：B
23. The government have realized the use the returnees make ______ the experience and skills ________while living abroad.
A．of, gained
B．of, gain
C．for, gained
D．up, gain
旋风分离器的出口有（）个。
A.2
B.3
C.4
D.5
