seven /ˈsevn/ num. 七，七个(人或物)；七岁：There are seven continents in the world. 世界上有七大洲。Two sevens are fourteen. 二七一十四。My son will be seven this year.我儿子今年就7岁了。
seventeen /ˈsevnˈti:n/ num. 十七；十七岁：seventeen years later 17年后；a list of names, seventeen in all一张名单，总共17人 He joined the Marines at seventeen.他17岁时加入海军陆战队。At the tender age of seventeen I left home.早在十七岁的小小年纪，我就离开了家。
seventeenth num.第十七
seventh /ˈsevnθ/ I. num. 第七(个)，七分之一(的)： two-sevenths 七分之二“G” is the seventh letter in the English alphabet. “G”是英语字母表上第七个字母。‖II. n. (月的)第七天: the seventh of July 7月7日
