在加工不通孔时的丝攻，为了捧屑方便，丝攻的容屑槽做成（）形式。
A.左旋
B.右旋
C.左排
D.右捧
参考答案：B
Some solid evidence proves that water really exists on Mars, but unfortunately, there is still no of life.
A．mark
B．sign
C．symbol
D．signal
巨盛一号金银花种苗为什么贵？
