在梯形图中常开触点与母线联结指令的助记符是()。
A、LDI
B、LD
C、OR
D、ORI
参考答案:B
给下列对话排序。
( ) Do you like pepper, too?
( ) Not on French fries. I like pepper on eggs.
( ) But I like salt on porridge!
( ) I like salt on French fries.
( ) Salt on porridge! Yecch! I like sugar on porridge.
如图所示为用“与”门构成的简易报警器的示意电路.当报警器发出警报声时,电键S1、S2处于的状态为( )
A.S1、S2都断开
B.S1、S2都闭合
C.S1断开,S2闭合
D.S1闭合,S2断开