5 Complete the sentences with must, mustn't, should or shouldn't and the verb. 1 It's a good idea to get up early. You should get up early. 2 It isn't OK to talk in the library. You quiet in the library 3 It is against the rules to eat sandwiches in the classroom We sandwiches in the classroom. 4 It isn't a good idea to talk and eat at the same time. You at the same time. 5 You can't use your mobile during a test. You your mobile during a test.