
淬火后的钢,随回火温度的提高,其强度和硬度也提高。


The state controls the country’s roads, but does little to reduce road accidents. As a monopoly, the government lacks _________ to provide better service, because there is no risk of ____________. But it does have incentive to collect more money from motorists who violate regulations. What the government does to _________ the problem, like _________________, _________, _________, cannot control accident rates. The bureaucratic solutions even complicate matters. The alternative to these solutions is better road design, for example, _________. A roundabout requires driver ______.and promotes an increase in ________________. It shows a new approach to address traffic problems. By studying the psychology and ________ of drivers, engineers can design ________________________ . The idea is not to _______ drivers’ behaviors with traffic lights, cameras or regulations, but to bring out their best driving behavior with better road designs.