tell me the difference between shuld and must

Must Used to express something formally required or necessary: I must complete the project by this week. The government must provide health care for everybody. Everyone must save the natural resources of the earth. The building must have a fire alarm. You must answer my question right now. Used to show that something is very likely: He must be a genius. You must be joking! There must be an accident. She must be very tired.

Should (past form of shall) Often used in auxiliary functions to express an opinion, suggestion, preference, or idea: You should rest at home today. I should take a bus this time. He should be more thoughtful in the decision-making process. Used to express that you wish something had happened but it didn't or couldn't (should + have + past participle) : You should have seen it. It was really beautiful. I should have completed it earlier to meet the deadline. We should have visited the place on the way. Used to ask for someone's opinion: What should we do now? Should we continue our meeting? Should we go this way? Where should we go this summer? Used to say something expected or correct: There should be an old city hall building here. Everybody should arrive by 6 p.m. We should be there this evening.