参考答案：D

解析：

根据上表中的净现金流量可以求得累计净现金流量如下：

句型转换  

1. We are cleaning the blackboard.(改为否定句)

      We ______  _______ the blackboard.

2. I am reading a book(改为一般疑问句)

     ________  ________  ________ a book?

3. Kate and Mary are talking about the pandas.(对划线部分提问)

     _________  _________ Kate and Mary talking about?

4. He isn't having lunch at home.(用every day改写)

     He _______ _______ lunch at home every day.

5. They are playing volleyball on the playground.(对划线部分提问)

      _________  ________ they _______volleyball?