单项选择题

Directions:
Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D on the ANSWER SHEET.
For most of the past 25 years, no single person or company has been powerful enough to control how the American Internet works. One 1 for that was the diffuse and chaotic nature of its online economy—a kind of 2 Wild West where thousands of producers 3 the attention of the masses. In this environment, no single company, not 4 giants like Google 5 Facebook, 6 enough traffic to bend the network’s free-market checks and balances.
The infrastructure of the Internet helped 7 everyone on a level playing field as well. All players, from individuals to 8 companies, had to pay an Internet service provider (ISP) a flat 9 , based on the speed or volume of the service, for online 10 . In 11 for those fees, the ISPs would expand and maintain their pipes and pass their customer’s traffic to and from another set of companies that owned the larger, global transit ways for online 12 . It was, for a time, a marvelous architecture, fundamentally unlike any of the other networks in American lives. There was no government ownership 13 with the interstate highway system, no 14 long-distance plans as with phone networks and no individual postage required to send content as with the U.S. Postal Service.
But in recent years, that unique 15 has started to crack, and the reason is the size of the biggest players. A decade ago, thousands of companies 16 in the daily buzz of Internet traffic, said Craig Labovitz, the CEO of DeepField, a network-research firm. By 2009, 150 companies 17 half of all that traffic, and by early this year, just 30 companies 18 the 19 of the daily give-and-take. As of March, just two companies in particular—Netflix and Google, which owns YouTube—accounted for 47% of all Internet traffic during prime-time hours at night, 20 Sandvine, a network-equipment company.

A.made up
B.made from
C.made of
D.made off