机械钻速是（）、地层岩性等因素的函数。
A、钻压
B、转速
C、钻头类型及尺寸
D、水力参数
E、钻井液性能
参考答案：A, B, C, D, E
James Schneider & Co. have written to us that they are the leading importer in your place dealing ______ chemicals.
A．with
B．in
C．about
D．for
—Do you know ______ he is going to stay in Shenzhen?
—Sorry, I don't know. Maybe a few weeks, but I'm not sure. [ ]
A. when
B. how long
C. what time
D. how soon
