Does she __________ a soccer ball?[ ]
A. has
B. have
C. are
D. is
答案：B
减温水调节门前后电动门的作用？
等离子弧焊必须对电极及喷嘴进行有效的水冷却，冷却水的流量不得小于( )。
A．2 L/min
B．3 L/min
C．6 L/min
D．8 L/min
