During the war there was a serious lack of food. It was not unusual that even the wealthy families had to （） bread for days.

A. eat up

B. give away

C. do without

D. deal with

下列关于惯性的说法正确的是（）

A.火箭升空时，火箭的惯性随其速度的增大而增大

B.做自由落体运动的物体没有惯性

C.战斗机战斗前抛弃副油箱，是为了增大战斗机的惯性

D.物体的质量越大，其惯性就越大