Generally speaking, the publishers will send you a specimen copy of their new books when .
A. requested
B. requesting
C. having requested
D. to be requested
网友回答
(答案→)A. requested
B. requesting
C. having requested
D. to be requested
解析:本题考查的是“when + 过去分词”作状语。when requested是when it is requested的省略形式。句意为:通常说来,如果需要,出版商会把他们的新书给你寄个样本来。