As engines get smaller, yet maintain the power density of a larger engine, the valves in them tend to take a greater beating.
发动机越来越小巧，却仍保留了大号发动机的动力密度，这时气门会承受更大的热量。
2
Let us know what you think and tell us what alternative search engine is your favorite. Also vote for the search technology you think stands the best chance of beating Google, in our poll.
让我们知道你的想法，告诉我们你在搜索引擎方面有没有什么偏好。
3
Microsoft Bing became the 2nd most popular search engine in North America, beating Yahoo for the position, according to AD network Chitika.