电动拉门在关闭过程中，如果遇到障碍物，门崩将返回到开门状态，延时（）自动关闭。
A.5s
B.8s
C.10s
D.20s
参考答案：C
妊娠24周以后，胎儿心音多在（）听得最清楚。
The boy is going to be a(n) _______ when he grows up, because he wants to be a person
like yang liwei.[ ]
A. pilot
B. engineer
C. actor
D. computer programmer
