“君子食无求饱，居无求安，敏于事而（）”。
A.慎于行
B.慎于思
C.慎于言
参考答案：C
_______for the captain ,the ship would have sunk with all on board .
A． Hadn’t it been
B．Had it been not
C．Not had it been
D．Had it not been
MB与SN通信时，用的是哪个时隙（）
A.0
B.2
C.4
D.6
