瓣膜置换术时，一般来讲人工瓣膜与术中测量的瓣口直径作比较应是（）

A.小4mm

B.小2mm

C.一样大

D.大2mm

E.大4mm

It has been said that most of the structural faults of technical reports result from the author’s () with what he is writing that he neglects to worry enough about how and for whom he is writing.

A. so much concerned

B. too much concerned

C. being so concerned

D. being too concerned