You may go now.和 You could go now.语气上有什么差别?

You may go home now.改成否定句 you may let her _____（go）back home now can you go fishing now? You must go home now you can___[go]home now may l go home now?if your homework( ),you can leave now may not的用法A:May I go swimming now?B:No,you ( ).You must fini May i go swimming now?no,you (mustn＇t/may not）.YOU must fini Could you please out now A not going B not to go C not go D now that you have finished your work,you may go and have a r ________ l go to buy it now?No,you _______.you may buy it on -May I go now?-No,you __.You __ stay here till 7:00o'clock.