the passenger had a chat with the college students ---as conductors during the summer vacation

问题描述:

the passenger had a chat with the college students ---as conductors during the summer vacation
A.to help out B.helped out C.help out D.helping out

答案:D.helping out 解析:1.此处的现在分词 helping out 用作 college students 的后置定语,意思是“帮助(他人解决苦难)的大学生”.分词与被修饰词为主谓关系,即帮助的行为是由大学生实施的.分词短语也可以改为定...