皮带机胶带的拉紧方法有重物拉紧和（）拉紧两种。
A.机器
B.电机
C.人力
D.机械
参考答案：D
什么是LKJ系统故障关机率？
She was not the woman ________ she was before．
A．what
B．who
C．that
D．where
