очень нужна ваша помощь--could, can, mustn’t, have to, needn’t, may, should, don’t have to

5 You ...practice more often if you want to improve your language.
6... we use the trade mark of your company?
7 You can stay out late if you like. You ...come home early.
8 We ...have done the work so quickly. We could have taken our time.