请解释桥机的工作速度包括哪几个机构？
参考答案：
起重机的工作速度包括起升、变幅、旋转和运行四个机构的工作速度。
—Are you having much trouble with the course?
— . The only thing I haven't understood so far is the reading we had last night.[ ]
A. Of course
B. Not likely
C. Not really
D. Not a little
入汤剂须后下的药是（）
A.苏合香
B.小茴香
C.肉桂
D.桂枝
E.细辛
