题目内容

【题目】He was observed ________ into the house before the owner came back.

A.to slip

B.slip

C.slipping

D.slipped

【答案】A

【解析】有人看到他在主人回来之前,溜进屋子.题干中用了observe sh do sth 的被动形式 be observed to do sth.

练习册系列答案
相关题目

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网