first和at first的区别?

first和at first的区别?

first有四个词形：adj. adv. n. pron. 这里主要谈adj.和adv.first adj. 序数词 第一的Example: He was the first student who arrived at the classroom. adv. 首先First I fed the baby. Then I made myself a sandwich.at first是一个介词短语在句中充当状语 首先At first I was nervous, but I soon started to relax.补充一个firstly 修饰句子的副词 首先 The plan was not practical, firstly because of the cost, and secondly because local people did not support it.通常可互用，但有差别，需查词典体会。