why isn't their water good to drink?

why isn't their water good to drink? Why isn't Tim happy with the parrot . The children ( ) doing their homework.A.aren't B.isn't C.don't D.not I don't know why Jack is worried;___,it isn't his his problem. I don't know why Jack is worried;___,it isn't his his problem. Why?I can't belive it!It isn't fair!的意思 为什么Why don't you不能写成Why do not you?Why isn't he 又为什么不能写成Why is not he? Their house isn't new .______选择题Their house isn't new .______a:Neither we areb:Neither are wec:Neither is oursd:Neither is our35 Do you know why he isn't in?同义句Do you know why he isn’t＿＿ ＿＿? why isn't there any Nobel-prize winner in ChinaChinese students are the most deligentin the world,why isn't there any Nobel-prizewinner in China? why she isn't famous?为什么WHY接的是陈述句,可以写成WHY ISN'T SHE FAMOUS或者WHY IS SHE NOT FAMOUS?仔细想一下是不是整句都是从句 句子转换同意句两个句子：This is your watch.That isn't their bedroom. If it isn't rain tomorrow,I'll help farmers with their work.单句改错 Our teacher is in the playground.But ____ (their/theirs) isn't. Everyone isn't here.=Not everyone is here?Why And translate them. ---Why isn't he very __ (sad)?----Because he is late for school.词形变化 [缩写]john is not boy.[用's还是isn't]?why? Why isn’t Sam happy?答句他找不到他的手表 说下怎么写