四川盆地年太阳辐射总量最少的原因是[ ]
A.多阴雨天气
B.纬度低
C.地势高
D.白昼短
答案:A
电气设备的“检修状态”的设备是指()。
A.所有断路器均断开
B.所有隔离开关均断开
C.悬挂标示牌
D.挂好保护地线或合上接地隔离开关
It has been laid down that each student must _____ a composition to the teacher once a week.
A.turn in
B.give up
C.put forward
D.bring out