Currently 2.5 million people employed by lnternte firms in the US not only enjoy an income about______but also enjoy themselves.
A.three times the national average.
B.three times as many as the national average.
C.more than three times of the national average.
D.as much as three times the national average.
肯定是A:Currently 2.5 million people employed by lnternet firms in the US not only enjoy an income about three times the national average,but also enjoy themselves.