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.
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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.