it much diffcult to control the quality when refinish

it much diffcult to control the quality when refinish it is diffcult to control and easy to west The quality control standards for quality control the Quality Control staff is respnsible( )quality of the pro 填空答案it's diffcult to d______ between the two. It is the first step that is diffcult to take It’s diffcult for me to finish the work. the _ of quality control and quality improvement extends bey It's diffcult for me to forget the sad to me. I find it diffcult to remember everything It is diffcult to dance____ (没有)music.