常见的螺纹紧固件中的螺纹是（）线（）旋螺纹。
A.单/右
B.多/右
C.单/左
参考答案：A
--- Where is your mother?
--- She _______ to Sichuan on business. She has ______ there four times recently.
A．has gone; gone
B．has been; been
C．has gone; been
D．has been; gone
下列不属于《政府采购法》的适用范围的是( )。
A．地域范围 B．主体范围C．时间范围 D．资金范围
