Question

【题目】I saw a street cleaner __________ the street when I went to school this morning.
A.clean
B.cleaning
C.to clean

Answer 1

【答案】B
【解析】句意：今天早上当我上学时，我看见一名街道清洁工在扫大街。根据短语see sb doing sth看见某人正在做某事，故此处用现在分词cleaning。故选B。