shall和should有什么区别和联系?

1.shall 用于第一、三人称的疑问句,表示征询对方意见和请示.多用疑问句
Shall he come in or wait outside?
Shall we make it next Saturday?
2.shall表示警告和强烈的建议：
The law of Venice says that if anyone tries to kill or murder any citizen of Venice,everything that he owns shall be taken away from him
The interest shall be divided into five parts,according to the agreement made by both sides.,declared the judge.
3.should 用于对将来进行虚拟的条件句中Should it rain tomorrow,the sports meeting will be called off.
4.用于if和in case 之后,表示某事不太可能发生,常译为“万一”,“以防……”.
If you should change your mind,do let me know.
Take your umbrella with you,in case it should rain.
5.用在名词性从句中,表示惊异、意外等情绪,常译为“竟然”.
（1） You can't imagine that a well behaved gentleman should be so rude to a lady.
（2） Well,I could never imagine an honest boy like John,should cheat in the exam!