列举几种车床的主要附件？
参考答案：
车床的主要附件有：卡盘、顶尖及鸡心夹头、中心架和跟刀架、心轴与弹簧卡头、花盘。
Corp. stock at a price of $60 per share. Kirk wishes to buy on margin. Assuming the margin requirement is 40 percent, how much money does Kirk have to pay up front to make the purchase（）
A. $36000.
B. $24000.
C. $0.
---Sorry. I must be off.
---How nice it would be if you_____a bit longer!
A．stay
B．would stay
C．stayed
D．have stayed
