The country itself didn’t have enough gas because of the war, so the government decided to  ________ its gas supplies to other countries.

A．hide away

B．cut off

C．insist on

D．break up

编写程序，一球从100米高度落下，每次落地后反弹高度为上一次高度的一半。求该球第 10次落地时所经过的总路程(保留两位小数)。