阅读短文，完成下列练习。
There aremany idioms in China. Most of them have only four Chinese words. But there arerich stories in the Chinese idiom book. Do you want to know more about theidioms? Let's take a look.
In theSpring and Autumn Period, the State of Wu and the State of Yue were neighbours.But there were always wars between them.
During onewar, Wu defeated Yue. Goujian, the king of Yue, was caught. Fuchai, the king ofWu, sent Goujian to do some hard work, like feeding horses. Goujian was veryangry, but he didn't say anything. He just did what Fuchai asked him to do. WhenFuchai got sick, Goujian looked after him day and night.
Threeyears later, Fuchai let Goujian go back to his own state. After getting home,Goujian began to plan his revenge(复仇). He didn't want to forget his hard time. So he slept on thebrushwood at night and tasted the gall every morning. The brushwood was coldand the gall was bitter, just like his days in Wu. Goujian kept asking himself,"Did you forget the past time three years?"
Goujianworked hard all the time. He worked with farmers and trained with soldiers. Hemade his people rich and his state strong. A few years later, Goujian led hisarmy to defeat Wu.
