影响性总结是指咨询者将来访者叙述的主题、意见等经组织整理后，以简明扼要的形式表达出来

The questions in this group are based on the content of a passage. After reading the passage, choose the best answer to each question. Answer all questions following the passage on the basis of what is stated or implied in the passage.

Dear Sirs,

Given all the coverage that the emergence of hybrid cars has received in your pages in recent months, your readers may be interested to learn that gasoline-electric hybrids are not a new phenomenon at all, but rather the latest incarnation of an idea that has been kicking around for over a century. Indeed, the hybrid car has been around almost as long as the automobile itself.

At the turn of the twentieth century, as the automotive age dawned, three power-generating technologies competed for dominance: steam, gasoline, and electricity. In the year 1900, steam was well known as the power source of the industrial revolution, and electricity was widely regarded as the power source of the future, so it was not at all obvious that internal combustion engines burning a fractional distillate of crude petroleum would have any particular edge in this race for the powertrains of America. Indeed, when engineer H. Piper filed the first patent application for a gasoline-electric hybrid motor in 1905, his intention was to use the gas to give a little kick to his perfectly serviceable electric engine. His goal: an engine that could accelerate from 0 to 25 miles per hour in 10 seconds.

Piper achieved his goal. Electric and hybrid-electric engines powered more than 35,000 vehicles sold in 1912. These cars were perfectly adequate for the time, but over the following decade they mostly disappeared from the market, through no fault of their own. The cause of their decline was the spectacular improvements in the cost and performance of gasoline-powered cars. An onslaught of fast and cheap internal combustion cars from Ford, General Motors, and Buick essentially buried the electric and electric-hybrid motors by the 1920s.

Continuing performance improvements in internal combustion engines and inexpensive gas pretty much kept hybrids buried until the oil crises of 1973 and 1979 gave Americans a reason to start thinking about fuel efficiency. Engineers had the motivation to think about fuel-efficient hybrids, but they still lacked the means to make hybrids economically competitive with gas-powered cars, because the performance of gas-electric engines lagged far behind that of gas-powered engines in acceleration, top speed, and cruising range.

Dramatic improvements in electronics and computer technology during the 1990s, however, finally made the hybrid a reality. Advances in battery performance and, most importantly, computer-guided electric power transfer created a car that could drive like a regular car, but do so on half the tank of gas. As another century dawns, perhaps we are entering into a new automotive age.

Based on the tone and content of the passage, the author of the passage is most likely which of the following ？（）

A. An automotive engineer writing to his company management

B. An enthusiast of automotive history writing to the editors of a car magazine

C. A college engineering student writing to a car manufacturer

D. A history professor writing to a television producer of historical documentaries

E. An environmental activist writing to the editors of a newspaper

某有机物的结构式如下：

则分子中有________个σ键，________个π键。

军队转业干部的住房，由安置地政府按照（）的原则给予保障。

A.统筹规划

B.优先安排

C.重点保障

D.合理负担

B737NG的发动机CFM56-7B的1发反推正常由哪个系统提供液压（）

A.系统

B.系统

C.备用系统

D.PTU

（）是房地产权属档案的生命，也是发挥档案的现实效用的基础和前提。

A.完整性

B.真实性

C.专业性

D.动态性