175. stem from: 起源于 A gradual agricultural revolution in northern Europe stemmed from concerns over food supplies at a time of rising populations. 源自于对不断增长的人口食品供应的担忧，一场渐进式的农业革命在北欧出现了。 stem作动词还可意为“阻止” The president decided to implement new laws to stem the flow of illegal immigrants. 总统决定实施新的法律，阻止非法移民流动。
176. indigenous to: 原产于…… This kind of fruit is indigenous to Africa. 这种水果原产于非洲。 indigenous people 原住民
177. bells and whistles: 华而不实的点缀品 I have found that men don't like too many bells and whistles. 我发现男性不喜欢太多华而不实的功能。 whistle in the dark 给自己壮胆；假装知道某事 He doesn’t know about this. He’s just whistling in the dark. 他不知道这件事，只是在瞎猜。
