钻水泥塞宜用铣齿牙轮钻头，可采用加重钻杆或加（）柱钻铤。
A.l～2；
B.3～4；
C.4～5；
D.5～6。
参考答案：A
I regret _____ you that my sister regretted _____ you her date. You are not the kind of person she wants. [ ]
A. telling; making
C. to tell; to make
C. telling; to make
D. to tell; making
调查食品安全事故，除了查明事故单位的责任，还应当查明哪些内容?
