There is a Chinese idiom（习语） ''tao li man tian xia"， referring to （指的是）a teacher who has taught so many students that they spread across the country like peach and plum（ 李子）trees．

The idiom comes from Zizhi， an official （大臣） that lived in the state of Wei（魏国） during the Spring and Autumn Period（BC770﹣BC476）． Zizhi was a knowledgeable person． He was not liked by the king at the time， so he had to leave his state． To make a living， he opened a private school and started to teach students．

As a teacher， he chose students no matter they were rich or poor． He often pointed at a peach and a plum tree in his yard when asking his students to work hard． "You should become a useful person and do work to benefit society， just like when the peach and plum trees bloom（开花）and bear fruit．" he said．

Keeping these words in their minds，many of Zizhi's students went on to different places around the country， achieving great things． They would plant peach and plum trees to show their respect（尊重） for their leather．

When Zizhi traveled around the country and saw his students and the trees they planted，he was very pleased．"My students are like peach and plum trees．They are everywhere，and they have achieved great results．"

（1）Why did Zizhi have to leave his state？ 　　

（2）How did Zizhi make a living after leaving his state？ 　　

（3）Was Zizhi pleased or angry when he saw the tree planted by his students？ 　　

（4）What kind of teacher was Zizhi？（至少写出两点） 　　

（5）What does "peach and plum trees" refer lo according to the passage？