完美笑容要有"黃金比例"

Dentists and researchers have come up with the formula for the perfect smile, from the size and width of each tooth to the curve, colour and shape of the teeth, and the overall width of the smile.

　　牙醫(yī)和研究學(xué)者已經(jīng)研究出完美笑容秘訣，從每顆牙齒的大小、寬度到牙齒的曲線、顏色和形狀以及張開的嘴寬度都有講究。