名词形式是first,意思是第一,最初; 头等; 一号,例如:
1.Take the first right, then the second left.在第一个路口向右拐,然后再在第二个路口向左拐。
2.His first music teacher was a major influence in his life.他的第一位音乐老师是他一生中对他影响非常大的人。
3.Mark has two children to support from his first marriage.马克得扶养他第一次婚姻生的两个孩子。