求一个句字解释we must balance the plane when it take offafter take-off,you could take any seat you like航空英语里面的.为什么起飞之前不能坐某个位置（为了飞机平衡）而之后可以坐?岂不是又不平衡了?

求一个句字解释we must balance the plane when it take offafter take-off,you could take any seat you like航空英语里面的.为什么起飞之前不能坐某个位置（为了飞机平衡）而之后可以坐?岂不是又不平衡了? 求解释一个初三的英语句子~我们必须在校园内禁止垃圾食品we must ban junk food from school’s我想问一下为什么用school‘s而不是school~求解释啊求解释~~~ we,must,do,we 怎么连词成句we,must,do,we 怎么连词成句 must,them,help,we连词成句. we must learn English well同义句 we must stop talking同义句：we ()talk any more We must do something.This is something.Therefore,we must do this.这话该如何解释 we must reach the post office as soon as we can同义句转换改写为we must 什么一个空to the post office as soon as什么一个空 we must keep animals from danger.（保持原句意思） we must ------ animals ------ danger. we must keep happy同义句转换we must keep happy___is____ ____ keep happy 2.we must keep animals from cruelty (保持句意不变) we must _____animals_________cruelty We must 这句的回答-We must call the doctor.We must call the doctor.Yes,we must.---这句的回答怎么是“we must”,而不是“we can”,用“we 用“we we must look after the old men 同义句 We must listen to our teachers.改成同义句. We must boil the water first.的否定句 must,obey,we,social,the,rules.连词组句 We must learn English well.(同意句）