Student or Learner
Would you be kind enough to explain to me the subtle difference between the meanings of the following sentences?
1.1.He must have closed the window.
1.2.He should have closed the window.
2.1. He had to do it.
2.2 He should have done it.
3.1. You neednít have repeated it.
3.2. He didnít have to repeat it.
Thank you for your efforts.