在如图7-74所示的RS触发器，设Q的初始状态为1，当输入X信号后，输出Q为（）。
A.X
B.
C.1
D.0
参考答案：C
—Jim, get up. It's time to _________.
—It's Sunday. We have no classes on Sunday.
[ ]
A. go to school
B. go to work
C. go home
D. go to bed
对一种化学物质进行发育毒性评价
强发育毒性一般母体／发育毒性比值（）
A.>1
B.>2
C.>3
D.>4
E.>5
