Explanation of "Should" and "Should not"

"Should" is a confusing word, because you can use it in different ways. Learn-English-Online.org describes several of them. Here is my version of the lesson on the website:

• To give advice or ask for advice ("You should always wear your hair like that--you look beautiful!" "Should I ask your brother to fix my car?")
• To communicate a strong opinion or instruction ("You should clean your bedroom right now!"). 
• To speak of things we regret doing or not doing (I shouldn't have become angry with my mother." "I should have helped my mother more."). 
• To speculate about (guess) what may or may not have happened ("Try calling your friend--he should be finished with his meeting by now.")
• To speculate about what may happen in the future ("It should rain tomorrow.").

My Suggestion: You can read the lesson about the different uses of should for yourself by clicking the link below:

"Should" and "Should Not" at Learn English Online