模拟基带信号对高频载波进行FM调制得到，其中的与_____成正比。

A、水

B、无机离子

C、溶解的气体

D、脂类

A、The conflict between friendship and war reality.

B、The conflict between forgiveness and hatred.

C、The conflict between common sense and war logic.

D、The conflict between sense of guilt and sense of duty.

设是零均值平稳带通随机过程，是其复包络，则关于的傅氏变换是的功率谱密度。

A、traffic lights

B、red and green lights

C、transportation lights

D、vehicle lights

A、The glass mountain represents the typical architecture of modern society: the skyscraper.

B、The climbing irons and plumber’s friends indicate the inadequacy of the character in dealing with the task ahead.

C、The fallen knights represent loss of tradition.

D、The "Enchanted Princess" represents beauty and nobility.