30.They are not allowed to go to school late. A.They don't have to go to school late. B.They mustn't go to school late. C.They must go to school late. D.They shouldn't go to school late. 31.You must phone her immediately; otherwise, you won't get any information. A.If you didn't phone her immediately, you won't get any information. B.If you phone her immediately, you won't get any information. C.Unless you phone her immediately, you will get any information. D.Unless you phone her immediately, you won't get any information.