下列不存在丁达尔效应的分散系是

A．有尘埃的空气

B．纯水

C．溴水

D．向沸水中滴入FeCl3饱和溶液所得液体

句型转换。

1. They have a baseball. (改为一般疑问句)

   _________ _________ a baseball?

2. Lily has a computer. (改为否定句)

    Lily _________ _________ a computer.

3. Does Mary have 4 baseballs? (作否定回答)

    No,_________ _________.

4. Her father watches TV every day. (改为否定句)

    Her father _________ _________ TV every day.

5. They have some balls. (改为单数句子)

   _________ _________ _________ ball.

6. This story is boring. (改为同义句)

     This story_________ _________.