1. 这是什么词？
词：engine
英英释义：something powerful that causes great changes in society
例句：China is one of the most powerful engines of the world economy.
2. 为什么选这个词？
我们很熟悉“engine”是“引擎”“发动机”的意思，和我们前面学习的许多名词一样，它也有引申的用法。像发动机可以带动机器运行一样，engine 常可以用来表示“可以引发巨大改变的事物”“带动发展的事物”，比如微信就是腾讯的 engine。
我们一起看几个例子。比如，有人说中国是带动全球经济增长最强劲的引擎之一，我们就可以说：
China is one of the most powerful engines of the world economy.
《纽约时报》在一篇名为 China Rules 的文章中回顾了中国的发展，说到中国社会结构转型时，有这样一段话：
Bureaucrats who were once obstacles to growth became engines of growth.
曾经阻碍发展的官员们，如今成为了发展的核心力量。
最新的一期《经济学人》中也出现了 engine 的这种用法：
The good reason for more powerful firms is the rise of an innovative elite that is an engine of efficiency.
更多巨头公司的出现得益于一批具有创新精神的精英群体的崛起，后者正是效率的驱动引擎。
3. 怎样学会使用这个词？
1）翻译下面的句子：
过去几年投资是中国经济的引擎，现在主要是消费在拉动中国经济。
（参考翻译：While invenstment was the engine of China's economy a few years ago, today it's mainly driven by consumption. 或 In the past few years, China's economy was driven mainly by invenstment, whereas today its engine is consumption.）
2）结合自己的生活、学习、工作、兴趣等，想象在什么语境下会用到这个表达。先简要描述这个场景，再造句。
场景1 ：科技创新是社会发展的引擎。
造句：Scientific and technological innovation is the engine of social development.
场景2：
造句：Exports and consumer spending are the country's main economic growth engines, which last year helped the economy grow by 4.8 percent.
China and India are currently the engines of world economic growth.
