3.结构成立+中文意思 = 正确的句子
who did (who) call you?
who did call you ? --> who called you?
who does (who) know him?
who does know him? --> who knows him?
what did (what) happen?
what did happen? --> what happened?
who is (who) crying?
who is crying? who
who is (who) going to come?
who is going to come? 或者 who is coming?