按要求改写句子。

1. —Did they meet John? (作肯定回答)

    —Yes, they          ．

2. I dropped my ice cream. (改为一般疑问句)

    ___  _ you _____ your ice cream?

3. She had sandwiches for lunch. (对画线部分提问)

                        she           for lunch?

4. —Did Lingling like fast food? (作否定回答)

    —No, ____          ．

5. Mrs Smart wants half a kilo of cheese.(对画线部分提问)

                         cheese does Mrs Smart want?

简述效率市场假说的类型。