依次填入下面一段文字横线处的句子，衔接最恰当的一组是一棵树就是一条竖立着的河流， ， ，树皮交错的纹路形如流水，从根部到梢头，就像从源头到下游，只是有些平静些， ；有些粗粝些， 。①重现风雨波澜②枝枝杈杈是分支流③树干是主河道④像水一样光滑

I am going to the supermarket to buy aquilt.— ________ You can easily buy one on theInternet.

In American there are more households withpets than ______ with children.

My mother wanted me _______ a doctorin the future .

－Can I park mycar here , sir?－______. Yousee, there’s much traffic here.