must, mustn' t  nedn' t
1.We haven' t got much time.We ... herry. 
2.We' ve got plenty of time.We ... herry.
3.We have enough food at home so we ... go shoping today.
4.Jim gave me a letter to post. I ... remember to post it.
5.Jim gave me a letter to post. I ... forget to post it.
6.There's plenty of time for you to make u your mind.You ... decide now.  
7.You ... wash those tomatoes.They' ve already been washed.
8.This is valuable book.You ... look after it carefully and you ... lose it  
9. what sort of house do you want buy?Something big?- well, it ... be big - that's not important.Buy it ... have a nice garden - that's essential.