"Google is not a conventional company.We do not I to become one,"wrote Larry Page and Sergey Brin,the search firm's founders,in a letter to investors ahead ofits stockmarket flotation in 2004.Since then,Google has bumished its reputation 2 0ne ofthe quirkiest companies on the planet.This year alone it has 3 eyebrows by taking a stake in a wind-energy project off the east coast ofAmerica and by testing self-driving cars,which have already_4 0ver 140,000 miles（225,OOOkm）on the country's roads.Google has been able to 5 such flights of fancy 6 its amazingly successful online-search business.This has 7 handsome returns for the firm's investors,who have seen the company 8 itselfin the space ofa mere 12 years from a tiny start-up into a behemoth with a$180 billion market capitalisation that sprawls 9 a vast headquarters in Silicon Valley known as the Googleplex.Google 10 stretches across the web like a giant spider,with a leg in everything from online search and e-mail to social networking and web-based software applications,or apps.All this has turned Google into a force to be reckoned with.11 now the champion of the unorthodox is faced with two conventional business challenges.The first 12 placating regulators,who fret that it may be abusing its considerable 13.On November 30th the European Union 14 a formal investigation into claims that Google has been 15 search results to give an unfair advantage to its own services-a charge the firm vigorously 16.The other challenge facing Google is how to find new sources of growth.17 all the experiments it has launched,the firm is still heavily dependent on search-related advertising.Ironically,investors'biggest worry is that Google will end 18 like Microsoft,which has 19 to find big new sources of 20 and profit to replace those from its two ageing ponies,the Windows operating system and the Omce suite of business software.That explains why Google's share price has stagnated.9选？

• A.across
• B.cross
• C.over
• D.through