为什么要加what's?It allows people to do a quick comparison,which is what's needed in the supermarket为什么不直接 which is needed 还要加what's?两个是否一样?

We think it's a good idea to allow teenagers to study in groups?为什么allow、study前加to? It is not allowed to go boating in the lake为什么allow要加ed But what happens if it rains?为什么happen要加sBut what happens if it rains?为什么happen要加s It maks 为什么要加s what does it mean的mean要不要加S what time is it begin?begin要不要加s 为什么要加what's?It allows people to do a quick comparison,which is what's needed in the supermarket为什么不直接 which is needed 还要加what's?两个是否一样? i am allowed to study at a friend's house 为什么allow加ed It’s known to all that.改成what is known to all is that 中为什么要加is?我说的意思是把it换成what，that后为什么要加is It’s known to all that.改成what is known to all is that 中为什么要加is?我说的意思是把it换成what，that后为什么要加is It essential that everybody know what to do 为什么 know不加s Knowing what these elements are makes it possible to use them consciouslyare后面的make为什么要加s?还有what能不能去掉?去掉好像差不多 为什么what makes good friend?make要加S? that's just what he wantedwanted为什么要加ed What's for dinner?中为什么要加be动词 What's your name?中的your为什么要加R? 英语询问某人职业为什么what要加's It's interesting to hear what the class think about action movies.为什么interesting后要加to啊?到底什么时候要加to什么时候不要加to啊?