We should consider the students’ request _____the school library provide more books on popular science.

A．that

B．when

C．which

D．where

浸在水中的苹果受到竖直__________的浮力，浮力的大小等于苹果排开的__________所受的重力．物体的沉浮取决于物体所受的_________与_________的大小关系．