You mustn't park your school bag when you hear the fire bell

You mustn't pack your school bag when you hear the fire bell You mustn't pack your bag when you hear the fire bell.保持句意不变 You must't pack your school bag when you hear the fire bell. You must not pack your school bag when you hear the fire bel what must or mustn't you do when the fire danger high you mustn't park your car here（保持原意） You mustn`t park your car here 改为 祈使句 Look at the sign.You mustn't park your car here.Oh,yes,I see must反意疑问句--You mustn't park your car here,sir;it's the entra Hurry up,don;t you hear the bell _______(ring)? -____ park the car here?-You mustn't,sir. you mustn't drop litter in the park 汉语意思