He had to pause from time to time to wipe the sweat from his forehead, because the air-conditioning system _________.

A．broke in

B．broke up

C．broke out

D．broke down

围生期包括胎儿期一部分和婴儿期一部分，国内普遍采用的定义是（）

A.胎龄27周至出生时

B.胎龄28周至生后7天

C.胎龄30周至生后2周

D.胎龄36周至生后4周

E.胎龄38周至生后1个月