题干
Mr. Smith couldn't open the door because his naughty boy _______ it from the inside
A：would lock
B：was locking
C：has locked
D：had locked
答案(点此获取答案解析）
D
Mr. Smith couldn't open the door because his naughty boy _______ it from the inside
A：would lock
B：was locking
C：has locked
D：had locked
