—Where's the chair?
—It's the floor. [ ]
A. under
B. on
C. in
D. of
答案：B
控制电路最终控制的是
A．灯丝电路的通断
B．电源电路的通断
C．高压次级电路的通断
D．高压初级电路的通断
E．保护电路的通断
It’s not safe to travel by standing at the road side hoping to be by passing motorists.
A．picked up
B．picked out
C．put on
D．taken on
