题目内容：

My wallet is missing,but I really don’t know _________it disappeared.
A.when it was that B.it was when that C.when was it that D.it was when
请详细说明选择理由,

优质解答

B it is/was ...that 是强调句型,可以省略
宾语从句用陈述句语气,所以B
我的钱包掉了,我真不知道它到底是什么时候丢的.