今天我们要学的词是rule of thumb。 Rule of thumb, 经过反复实践，得出的一般规律。一项最新研究指出，少吃能长寿。 "The rule of thumb is that by eating 15 % less starting at age 25 you could add 4.5 years to your life," 一般规律是，如果你从25岁开始，饭量减少15%，就能多活四年半。

如今油价飞涨，省油的高招之一是： "As a rule of thumb, shut off your engine if you expect to be sitting for more than 30 seconds," 一般来说，如果停车超过半分钟，就应该熄灭引擎。好，今天我们学习的词是rule of thumb...