While the boy down the street, the UFO .
A. was walking; was landing
B. walked; landed
C. was walking; landed
D. walked; was landing
网友回答
A. was walking; was landing
B. walked; landed
(答案→)C. was walking; landed
D. walked; was landing
解析：根据语境可知此句的含义是这个小男孩沿着街道走的时候，ufo正在着陆。此题重点考查的是while引导的状语从句表示当…的时候。其强调的是两个动作同时进行，并且经常用进行时态，故选C。