麻花钻是钻孔最常用的刀具，一般由（）制成，工作部分有两条对称的螺旋槽，是（ ）和（ ）的通道。（各项用顿号分隔开）

sk 5 Directions: The following is a business letter. After reading it, you should give brief answers to the 5 questions （） to your Gmail account, just visit: The Gmail Team 56. Why does the Gmail Team write to the Gmail user Because the user hasn’t used his / her Gmail ________ for quite some time.