现代机床夹具的发展要求既要夹具结构标准化，又要夹具零部件标准化。
参考答案：对
—The plane is due to take off at 7:50 from the airport.
—________ we fail to arrive there in time?
—Try to take another flight then. [ ]
A. What if
B. As if
C. Even if
D. Only if
（）级台风会对香蕉园造成破坏？
A、5级
B、6级
C、7级
C、8级以上
