按要求做下列句子，每空一词。

1. Our class has fifty students. (句意不变, 改写)

    _____ _____ fifty students in our class.

2. Mary does her homework in the evening. (改为一般疑问句)

    _____ Mary _____ her homework in the evening?

3. There is a little water in the glass. (改为特殊疑问句)

    _____ ______ water is there in the glass?

4. Her friend has lunch at school. (改为特殊疑问句)

    ______ ______ her friend have lunch?