（ ）指令可用来等待数字输出信号为 0。
A: wait(D_OUT[11], ON)
B: wait(D_IN[11], ON)
C: wait(D_OUT[11], OFF)
D: wait(D_IN[11],OFF)
A: wait(D_OUT[11], ON)
B: wait(D_IN[11], ON)
C: wait(D_OUT[11], OFF)
D: wait(D_IN[11],OFF)
举一反三
- The salesman had to ______ the conversation in order to wait on a customer. A: break off B: break away C: break in D: break out
- I think we should wait for Jimmy. He never ______ on time. A: call off B: ran into C: turns up D: find out E: hang on
- _______ you please _______ a minute ? A: Would…wait B: Do…wait C: Shall…wait D: May…wait
- He didn’t know () or go home. A: if to wait B: to wait C: whether to wait D: either to wait
- He didn't know or go home. A: to wait B: if that he should wait C: if to wait D: whether to wait