Please stand-by()channel 12.
A、to
B、on
C、at
D、in
A、to
B、on
C、at
D、in
A、If the first stand-by set failed B、If the first stand-by set fails C、If the first stand-by set will fail D、If the first stand-by set doesn’t fail
A、the main engine in the stand-by condition B、auxiliary machinery in the stand-by condition C、dynamical equipments in the stand-by condition and could be used immediately D、A and B
A、to get the engine ready B、to respond to the engine C、to maneuver the engine D、to change the engine