【题目】It was in the early 1990s that cartoons began to take off in China, ________ there were only picture-story books.
A. where B. when C. after that D. before which
在线课程【答案】D
【解析】考查介词和定语从句。句意：在90年代早期卡通片开始在中国盛行，在此之前中国只有图画书。先行词为the early 1990s，表示在此之前用介词before，关系词代指the early 1990s，故用which，故选D。