A、Growth
B、maturity
C、decline
D、introduction
A、Growth
B、maturity
C、decline
D、introduction
Ⅱ. Please translate the underlined part of the following scientific writing. Fog can pose a serious hazard to both surface and air travel. Many auto accidents and ship collisions and aircraft crashes have been attributed, at least in part, to visibility restrictions caused by dense fog. Fog frequently forces flight delays, reroutings and cancellations that cost airlines millions of dollars each year and inconveniences for thousands of passengers. Although the need for an effective method of fog dispersal is great, especially at airports, little progress has been made in this area for both technical and economic reasons. During World War II, the British had considerable success in clearing warm radiation fogs from runways at 15 military airfields. Heat from fuel burners deployed alongside runways raised the air temperature, thereby lowering the relative humidity to below saturation so that fog droplets vaporized. With shallow radiation fogs at airports, some clearing may be achieved by using helicopters to induce vertical circulation of air. The rotor blades force the warmer unsaturated air that is just above the fog layer to mix with it. Humidity of the mixture falls below 100 percent, and fog droplets vaporize. Another approach to fog dispersal applies techniques of cloud seeding. Warm fogs are seeded with hygroscopic substances that absorb water vapor, thereby reducing the relative humidity by reducing the vapor pressure. Fog droplets vaporize, and hygroscopic droplets grow into raindrops that fall to the surface. Cold fogs (-10 to -20C0) are seeded with dry ice pellets that stimulate the Bergeron process.
The police __________the evidence by legal means that George murdered his wife. |
[ ] |
A. achieved B. gained C. obtained D. contained |
为了保护您的账号安全,请在“简答题”公众号进行验证,点击“官网服务”-“账号验证”后输入验证码“”完成验证,验证成功后方可继续查看答案!