tooth简单

“Nature gave us lips to conceal our teeth,” ran one popular Victorian saying, alluding to the fact that before the birth of proper dentistry, mouths were often in a shocking state of hygiene.

维多利亚时代流行的一句俗语说：“大自然给了我们嘴唇来遮住牙齿。”这暗指在正规牙科诞生之前，人们口腔的卫生状况往往糟糕得惊人。

A toothy grin (especially when there were gaps or blackened teeth) lacked class: drunks, tramps, and music hall performers might gurn and grin with a smile as wide as Lewis Carroll’s gum-exposing Cheshire Cat, but it was not a becoming look for properly bred persons.

露齿的笑（尤其是牙齿有缝隙或发黑时）显得缺乏格调：醉汉、流浪汉和杂耍剧场的演员可能会做鬼脸、咧嘴大笑，笑容宽得像刘易斯·卡罗尔笔下露出牙龈的柴郡猫，但对于有良好教养的人来说，这可不是得体的样子。

In an experiment published in 1988, social psychologist Fritz Strack of the University of Würzburg in Germany asked volunteers to [hold] a pen either with their teeth — thereby creating an artificial smile — or with their lips, which would produce a(n) [disappointed] expression.

在1988年发表的一项实验中，德国维尔茨堡大学的社会心理学家弗里茨·斯特拉克让志愿者要么用牙齿咬住一支笔——由此制造出一个假笑——要么用嘴唇含住笔，这会产生一种失望的表情。