夹层腹主动脉瘤主要见于（）
A.高血压
B.主动脉缩窄
C.外伤
D.不当的主动脉插管术
E.Marfan综合征
参考答案：A
--- Would you mind not littering in the classroom?
--- ______. I’ll pick up the waste paper.
A．With pleasure
B．Thanks
C．No, not at all
D．Yes, that’s all right.
滚珠在循环回路中与丝杠脱离接触的滚珠丝杠，称内循环滚珠丝杠。( )
