Rewrite the following sentences so that the meaning does not change using the words given in parentheses using negative forms if necessary

Rewrite the following sentences so that the meaning does not change using the words given in parentheses using negative forms if necessary
1. it is not good for you to spend too much time playing video games.(should)
2. it i essential that you tellyour parents before you go out.(must)
3. nam is taller than his father.(shorter)