UNIX系统采用了进程对换的内存管理机制和______的存储管理方式，实现了虚拟存储管理。
参考答案：请求调页
Graham-Steell杂音见于（）
A.二尖瓣狭窄
B.三尖瓣狭窄
C.肺动脉瓣关闭不全
D.二尖瓣关闭不全
E.主动脉瓣关闭不全
A hygroscopic cargo is define as a cargo（）.
A.capable of absorbing moisture in the form of a gas
B.capable of giving off moisture in the form of a liquid
C.that is shipped in a liquid stste
D.that will ignite in contact with water
