（）安装方便，定位准确，可多次拆卸。
A.开口销
B.圆锥销
C.槽销
D.圆柱销
参考答案：B
I’m sorry to hear that you failed your driving test. _____luck next time.
A．Good
B．Better
C．Best
D．The best
6□84的1≈61万，□里可以填______．
