问题补充：
------“Where was Li Ming last night ?”
------“I saw him his homework in the classroom.”
A. was doing
B. did
C. doing
D. to do
答案：
A. was doing
B. did
(答案→)C. doing
D. to do
解析：考查现在分词做宾语补足语：句意：--黎明昨天晚上在哪里？--我看见他正在教室做作业。See sb doing“看见某人正在做”，doing是现在分词做宾语补足语，选C。
