为什么用is?

为什么用is? 为什么这里用is? 为什么要用is is he your friend,为什么用is? this is kangkang.为什么用this is twenty yuan is ok.为什么用is? all is well为什么用is there is no friends为什么用is stealla is here.为什么这里用is? 老师,为什么tomorrow is Sunday用is The news is very important 为什么用is?The news is very important 为什么用is? There is a little sheep on the hill 为什么用is为什么 用is neither of them is right ,is he?为什么用 is he 而不用is it? 为什么肯定用it is ,否定用he is She is very young.这里为什么要用is reading is fun l like it为什么用is Three and five ( is)eight 为什么用“is” there is some milk为什么要用is