键的剖面尺寸b×h通常是根据（）从标准中选取。
A、传递的转矩
B、传递的功率
C、轮载的长度
D、轴的直径
参考答案：D
有28名同学去划船，每5人坐一条船，这些同学需要几条船？[ ]
A.5
B.6
C.7
D.4
—What terrible noise here!
—Go to tell the children that they are ____ to be quiet here.
A．hoped
B．promised
C．thought
D．supposed
