题目内容：

    At first glance,price-comparison websites are an example of capitalism at its best.But it has caused fierce competition on price and eviscerated profits.Towers Watson,a consultancy,said that "unnecessary" price competition following the rise of comparison sites in Britain had cost insurers ￡1 billion a year.

Consumers should celebrate that;the firms' losses are their gains.But there is a catch.Comparison sites introduce a new layer of costs,including their own advertising campaigns.In theory,competition in the market for comparison sites ought to keep those costs down.But David Ronayne of Warwick University argues that consumers often lose out from comparison sites.They earn a commission for each shopper who uses them for consumption such as buying insurance.That referral（委托）cost is included in the price the consumer ends up paying.If the increased costs outweigh the saving the comparison enables,consumers end up worse off.

These worries are not just theoretical.In 2014,Britain's competition regulator found that many comparison sites were using their contracts with retailers（零售商）to ban them from offering lower prices elsewhere.That weakened rivals' incentive（对手的动机）to cut fees,because prices on their site could not fall.By keeping prices similar,the contracts also reduced the incentive for consumers to search on multiple sites,thus helping sites retain their users.

Weaker incentives to lower commissions mean weaker incentives to lower costs,too.That might explain why comparison websites advertise so heavily,and sometimes offer free gifts to those who use them.In a recent paper,Ben Edelman of Harvard Business School and Julian Wright of the National University of Singapore argue that when a site knows that the prices merchants provide through it will always be the lowest available,it increases investment in attracting customers,safe in the knowledge that the merchants and at last consumers will bear the cost.

Is there any way to ensure the market for price comparison is competitive?Asking consumers to check multiple websites defeats the point of using them.One solution is to have only one site,but regulate it as a public utility（功用）. Alternatively,the governments could run the site itself.But creating good search and comparison sites may be too hard for them.It is much better to acknowledge that consumers will always have to do some comparison themselves to "keep the system honest".

Websites that compare the comparison sites can help,although it is easy to see how they could fall prey to the same problems.Any firm with captive users（被动用户）,be it a comparison site a search engine,or a social-media platform,can charge a high price for access to the eyes of its customers.For all their innovation,Internet middlemen are not unlike supermarkets.Shoppers would never imagine that a single store had the lowest price for all the items they need.

1.According to the first two paragraphs,price-comparison websites______.

A.will offer smart consumers the best deals

B.will bring insurance firms increased profits

C.can help keep the costs of insurance firms down

D.may raise the price that consumers pay for their purchases

2.Current comparison sites tend to put most of their efforts in______.

A.lowering commissions B.contracting with retailers

C.attracting consumers D.cutting operating costs

3.According to the last two paragraphs,the author probably agrees that______.

A.it's desirable to have only one comparison site and have it run by the government

B.it's advisable that comparison sites with captive users charge a high price for its service

C.consumers should check multiple comparison sites before making a purchasing decision

D.websites that compare the comparison websites can help to build a competitive market

4.The passage mainly conveys the idea that comparison sites______.

A.create an effective channel for smart consumers

B.are competition's friends and enemies at the same time

C.offer win-win deals between consumers and retailers

D.have caused a new form of competition among retailers