单发活塞发动机飞机左、右油箱连通管的作用是：（）.
A.用于油箱间的油液传输
B.保持两油箱均压
C.用于清洗油箱
D.用于加油
参考答案：B
There are in a season.[ ]
A. three years
B. three months
C. three weeks
D. three month
After all, the candidate was endorsed by the governor's board and many of the local party members.
A．sponsored
B．approbated
C．recognized
D．rejected
