______in the past, at the moment it is a favorite choice for wedding gown.

A. Unpopular has as white been

B. White has been as unpopular
C. Unpopular has been as white

D. Unpopular as white has been

减少与抑制散射线的方法不对的是

A.使用滤线器

B.空气间隙法

C.增加附加滤过

D.扩大照射野

E.使用准直(遮线)器