Fill in the blanks. Use:should/shouldnt/must/neednt/have to. Shall I buy some butter?-No,you ... . We ve got some. What

1. Shall I buy some butter? — No, you shouldn\'t. We\'ve got some.

2. What should I do to pass the chemistry exam? — You must work hard and spend more time doing your homework.

3. Excuse me, I have to get to Trafalgar Square. Should I take a bus? — Yes. You should take bus № 62.