4PSK常称为正交相移键控（QPSK）。它的每个码元含有2b的信息，用ab代表这两个比特，有4中排列，即00、01、10、11，用4中相位之一去表示每种排列。
查看答案
Which of these statements sums up the article best?Internet advertisers........
A. are only interested in the number of people who click on advertisements.
B. don't know how to avoid users 'clicking away' from advertisements.
C. are looking at ways of engaging users so that they do not click away from advertisements.
Find idiomatic expressions in the article heading which means:
Match the words in bold in the word pairs 1-5 to their meaning A-E.
微信支付 
支付宝支付