n.三個(gè)一組；三合會(huì)；三和弦
This coordinate system is called the triad at the point. 這個(gè)坐標(biāo)系叫做該點(diǎn)的三面形坐標(biāo)系。
Healthy living means the triad of behavior: diet, physical and mental exercise. 健康的生活方式是飲食、身體鍛練和思維鍛練的三合一。
