大型吊拖船队上行遇山角、矶头附近的回流时，应（）.
A、充分利用
B、尽量避开
C、充分利用上部回流
D、驶入主流
参考答案：B
Passage TwoQuestions 29 to 31 are based on the passage you have just heard.
A．They often ride a motorcycle.
B．They used to ride a horse.
C．They work in the mountains of Canada.
D．They ride a horse.
我国的瘦肉型猪种养殖已经发展成为养猪业的主导类型。( )
