题目内容：

句型转换

1.When did people invent the bus? (改为被动语态)

When ________ the bus ________？

2.The potato chips were invented by mistake. (对画线部分提问）

________ ________ the potato chips invented?

3.It was invented by Whitcomb Judson. (对画线部分提问）

________ ________ it invented by?

4.They sold the computer at a low price. (改为被动语态）

The computer ________ ________ at a low price by them.

5.It is used for serving cold ice-cream. (对画线部分提问）

________ ________ it used for?

6.It was summer, but the beach was cool in the morning. (同义句转换）

________ ________ it was summer, the beach was cool in the morning.