地铁与轻轨划分的原则（）。
A、运行列车的重量
B、轨道承受的荷重
C、运行速度的快慢
参考答案：B
"汹涌发酵"现象见于（）。
A.产气荚膜梭菌
B.嗜水气单胞菌
C.破伤风梭菌
D.肉毒梭菌
E.溶组织梭菌
A: Did you buy the book B: ______
A．No. On my way home from work I found a bookstore and entered aimlessly.
B．I had no idea the bookstore would close at six.
C．Excuse me, I didn't buy the book purposely.
D．I like it very much.
