Complete the sentence with: must, mustn't, should, shouldn't 

Complete the sentence with  " must , mustn't , should  , shouldn't  "
1 children ...spend too much time playing video
games 
2 students ... finish their homework before watching TV 
3 we  ... go to school or work by bus 
4 he  ... take part in activities with their friends 
5 you ... keep off the grass 
6 children  ... play in the street 
7 Tim ... come home before 10 o'clock 
8 they  ... eat less fast food because it is good for their health