The marine diesel engine is a type of dies
题型:单项选择题
问题:
The marine diesel engine is a type of diesel engine used on ships The () of its operation is not very difficult to understand.
A.principle
B.principal
C.cause
D.case
The marine diesel engine is a type of diesel engine used on ships The () of its operation is not very difficult to understand.
A.principle
B.principal
C.cause
D.case