下面关于随机存取存储器(RAM)的叙述中，正确的是______。

A．RAM分静态RAM(SRA和动态RAM(DRA两大类

B．SRAM的集成度比DRAM高

C．DRAM的存取速度比SRAM快

D．DRAM中存储的数据无须“刷新”

Competing in sports can not only ________ one's strength, but also develop one's character.[ ]

A. bring up  

B. take up

C. build up  

D. pull up