【单项选择题】
The younger motorman as well as the others () to operate the oil separator.
A、A.has learnt
B、B.have learnt
C、C.learn
D、D.are learning
A、A.has learnt
B、B.have learnt
C、C.learn
D、D.are learning
A、the bridge officer on watch B、the chief engineer C、the duty engineer D、the duty motorman