The basic unit of measure in a computer system is the（ ）. It is the smallest unit in computing. There are some other measures in a computer, such as Kilobyte,Megabyte, Gigabyte and so on.

A．Kilobyte

B．Bit

C．Gigabyte

D．Megabyte

下列不能说明重力的方向竖直向下的是[ ]

A．电灯使电线竖直静止

B．苹果从树上落下

C．质量越大的物体越重

D．抛向空中的物体最终会落到地面上