请教This case doesn't belong to me为什么不是This case isn't belong to me

请教This case doesn't belong to me为什么不是This case isn't belong to me 看下这句This case doesn't belong to me为什么不是This case isn't belong to me This case doesn't belong to me!这句中to起到什么作用? Do与Does的区别?This case doesn't belong to me.This case don't belong to him.Do与Does的区别?This case doesn't belong to me.This case don't belong to him.我知道Does是第三人称单数用的形式,其他形式用do.为什么第一话用的 this radio doesn't work this doesn't always happen This case doesn't(/isn't) belong to me!这个箱子不属于我!This case doesn't(/isn't) belong to me! 这个箱子不属于我!问：如果换成括号里的isn't对吗? ,如果不对是为什么呢?.什么情况可以用isn't? It doesn't matter this time. i doesn't like this colour.改错 what doesn't this passage tell It doesn't count this time,try this dish t______ delicious,doesn't it? This machine _______.It hasn’t worked for years.A.didn’t work B.wasn’t working C.isn’t working D.doesn’t work—I’m afraid Mr Wood can’t see you 4 o’clock.—Oh,_____I won’t wait.A.no doubt B.after all C.in that case D.in this way This case doesn't belong to me与These keys don't belong to him为什么 1句用DOES 2句用DO 在这的助动词是修饰的 this case还是 me does明明是修饰第三人称单数的呀 连词成句.has,three,pencil case,Lily,but,doesn‘t,pen,she,have,a 请翻译She doesn't let him leave the train in case he gets lost She doesn't have enough money for this book翻译 He doesn't think this book is interesting.有错吗?