普通十字万向节允许两轴交角达（）度，一些等速万向节最大交角可达（）度左右。
参考答案：15°---20°；45°
— Who is Jerry Cooper?
— _______ ? I saw you shaking hands with him at the meeting.[ ]
A. Don’t you meet him yet
B. Hadn’t you met him yet
C. Didn’t you meet him yet
D. Haven’t you met him yet
对登机旅客及装入货舱的行李、货物的数量应当仔细核对，发现可疑人员或物品必须禁止登机或装机。（）
