当额定电流630A以上时，推荐采用( )。
A．密集绝缘型母线槽
B．空气密集绝缘型母线槽
C．插接式母线槽
D．滑接式母线槽
参考答案：A
---Could you tell me when your father___back?
---I’m not sure now. but when he ___next week, I’ll tell you.
A．return, comes
B．will come, returns
C．comes, will return
D．will return, comes
温带草原是能流和物流速度较快的生态系统。 ( )
