What does this sign mean?=what is the meaning of this sign? 8.Where can we find it?我们在哪里能找到它? 9.Which door must we use?我们必须要使用哪一扇门? 情态动词的一般疑问句就是把情态动词提前,后面照抄。句号改为问号。 Must we wait for the green man? 10.the one on the left/right ...