轨道上有油或冰霜时，车轮将会发生打滑现象。（）
A、正确
B、错误
参考答案：A
_________ the meeting room, he found all the parents already ________ there.
A．To enter, sitting
B．Stepping into, to seat
C．Entering, seated
D．Entered, seat
Is this the way you think ____________solving the problem?[ ]
A. of
B. of to
C. about
D. of of
