问答题 Part 1. Complete the sentences below with the words in the box. Change the form where necessary. Each word can be used only once. （20 points, 2 points each）   device    mode   contrast   campaign    assess    plagiarism undermine    exemplify     access     acquire 2. Most students attend a university mainly to _________ the knowledge needed for their chosen profession.

单项选择题 DPSK属于： A、相位调制 B、幅度调制 C、频率调制 D、混合调制

多项选择题 可以用来判断现象之间相关方向的指标有（ ）。