4．
语法填空
There were many people on a bus. An old man (look) here and there. He wanted to find empty seat. Then he saw one and went to it. A small bag was on the seat. And a young man was beside it.
"Is this seat empty?" asked the old man.
"No, it's an old woman. She went to buy some bananas," said the young man.
"Well, let me sit here, please. I'll leave here when she (come) back," replied the old man.
After a few minutes, the bus started. The old woman (not come), but her bag was here. "Let me give her the bag." Then the old man threw the bag out of the bus window.
The young man jumped up and shouted, "Don't throw! It's my bag!"
