管理信息系统开发采用的生命周期法中，系统运行和维护阶段的主要工作是：（）A.对系统评

对外“用一个声音讲话”，“建设欧洲人的欧洲”，这说明欧共体的目的是  [ ]

A、独霸欧洲

B、遏制 * * 主义

C、谋求欧洲的安全、独立和发展

D、同美、苏对抗

进口货物的收货人可以在报关地或收货地委托代理报检单位报检。 ( )

汽油发动机转速特性是在化油器调整适当（）维持最佳值，节气门开度一定的情况下得到的。

A、进气持续角

B、排气持续角

C、点火提前角

D、喷油提前角

新生儿出生后2~3天出现黄疸最常见的是：（）

A.新生儿肺炎

B.母乳性黄疸

C.胆道闭锁

D.生理性黄疸

E.败血症

Jim Boon is a hybrid kind of guy. He drives a Toyota hybrid to work, a Honda hybrid on weekends and, as a manager for Seattle public transit he recently placed the world’s largest order for hybrid electric buses.

Now, with the biggest hybrid-bus fleet in the world, Seattle has become the main testing ground for a technology that claims it can drastically cut air pollution and fuel consumption. In the 1990s, demo fleets of 35 buses or fewer started cropping up in cities such as Tempe, Ariz. Sixteen of these early hybrids still service Genoa, Italy, where drivers switch from diesel to electric power when passing the city’s downtown architectural treasures. But no city has gone as far as Seattle, which last year bought 235 GM hybrid buses at $ 645,000 a pop. When the final one rolls out this December, the region’s bus system will be 15 percent hybrid.

But why Seattle, and why now The Pacific Northwest has long been a hotbed of both Green politics and cutting-edge technology. Fourteen years ago the Seattle area bought 236 Italian-made Breda buses to service a mile-long downtown tunnel. They were supposed to operate as clean electric trolleys underground, but the switching mechanism often failed and "the bus drove through the tunnel as a diesel," says Boon. "It was pretty loud and smoky. "

When the Bredas hit retirement age in 2002, Boon went shopping. He chose the GM buses because they use an automatic transmission and diesel boosters that provide power to scale inclines without strain. In hilly Seattle, the prospect of a hybrid that could climb like a diesel but accelerate without belching black fumes helped justify a price $ 200,000 higher than that of a regular bus. "The days of seeing a diesel pull away and pour out smoke are over," says Boon. "After we drove these hybrid buses across the country, I wiped a handkerchief inside the tailpipe. It came out spotless. "

Experts say buses are critical to realizing the hybrid dream of greater efficiency and cleaner air. It would take thousands of hybrid cars to save as many gallons of gas (750,000) as Boon expects his buses to save Seattle each year. GM claims that compared with conventional diesels, its new buses also churn out 90 percent less particulate matter—a known carcinogen. "Buses are a major source of pollution in any city," says Dave Kircher of the Puget Sound Clean Air Agency. "They operate where people are breathing this exhaust, so this is a major step forward in terms of emissions. "

And a major step forward in the marketplace: Philadelphia, Honolulu, Long Beach, Calif., and Albuquerque, N. M. , have all bought the GM buses in recent months. GM is now touting itself in ads as the top hybrid-bus innovator, but Siemens is among the global giants dueling GM for new business, and New York plans to deploy 325 BAE Systems hybrids by 2006. "There’s room for competition," says James Cannon, editor of Hybrid Vehicles newsletter. Seems Seattle isn’t the only city trying to leave grunge behind.

Why are buses critical to realizing the hybrid dream of higher efficiency（）

A. Buses are a major source of pollution

B. A single bus saves much more gas than a single car

C. Buses carry more passengers

D. New buses produce less harmful material