營養物質循環的后期與前期相比，封閉性增強，循環速度______。
2歲內小兒心尖搏動的位置是（）
Thenewdiscovery_______beofgreatservicetomankind.
Williamhascuthissmoking_____tofivecigarettesaday.
Thefurnitureinherbedroomisquitedifferentfrom________inthelivingroom.
Thehostsapologizedfor______thatsomeoftheirguestsmightbevegetarians.
