Can you please tell me the difference between "should" and "must" and when we have to use them

Answer 1

Must is something you are required to do.
Should is something that could be optional but you feel compelled to do it or it reaps benefits.

Example:
I should study for my test tomorrow.
I must study for my test tomorrow.

The second sentence shows more urgency and importance in studying for the test. The first sentence shows it is important to study for the test tomorrow but not to as high of degree as the second. If I was to say I must study for my test tomorrow. I would study for my test. But if I say I should study for my test, I still might not study for my test. I should do it because I want a good grade, but if I don't life goes on.

Answer 2

Must is something you are required to do.
Should is something that could be optional but you feel compelled to do it or it reaps benefits.

Example:
I should study for my test tomorrow.
I must study for my test tomorrow.

The second sentence shows more urgency and importance in studying for the test. The first sentence shows it is important to study for the test tomorrow but not to as high of degree as the second. If I was to say I must study for my test tomorrow. I would study for my test. But if I say I should study for my test, I still might not study for my test. I should do it because I want a good grade, but if I don't life goes on.

Answer 3

"Should" refers to something that is suggested. "You should use an umbrella if it rains." It doesn't mean you have to use one, but it is beneficial to do so. It is your choice if you get wet...

"Must" refers to something being necessary. "I must get to the doctor today." It implies that you absolutely have to do this, and intend to make it a priority to do so.

Answer 4

I should answer this question, but that Arny just nailed it... his/her answer is the best.. so you must choose it!

Answer 5

Should is a suggestion or advice.
Must is an imperative.