We all know that,             , the situation will get worse.     [      ]

A. not if dealt carefully with    

B. if not carefully dealt with    

C. if dealt not carefully with    

D. not if carefully dealt with

制样过程中，粒度小于3mm煤样，缩分至3.75kg后，必须使之（），则可用二分器直接缩分出（）制备分析煤样，也就是可以免除（）这一环节