first在这里是做副词用,意为“首先”.at first不能放在句子中间,只能放在句首或句尾
从用法上看区别
1.first的用法
first 用来说明顺序,意为“先……”,暗示接下去还有其他动作或事件要发生,因此其后往往接有(或暗示有) then,next,last 等词.如：
Think first,then act.先想清楚再行动.
I’ll have to finish my homework first.我得先把作业做完.
First (you) boil some water.Then (you) warm the teapot.Then (you) add three teaspoons of tea.Next,(you) pour on boiling water...你先烧些开水,然后把茶壶烫热,接着放三勺茶叶,随后冲入开水……
John came home from work.First he read the paper for a while,then he got up from the chair and turned on the radio.约翰下班回家,先看一会儿报,然后从椅子上站起来,打开收音机.
2.at first 的用法
at first 的意思是“起初”“开始”,它主要用于强调前后对照,暗示接下去的动作与前面的动作不同甚至相反,因此有 but,afterwards,soon,at last 等相呼应.如：
At first I didn’t want to go,but I soon changed my mind.我开始不想去,但我很快就改变了主意.
The work was hard at first,but I got used to it.起初这活儿很累,不过后来我习惯了.
At first they were very happy,but then things started going wrong.起初他们生活得很幸福,但后来就开始出问题了.
At first I paid little attention,but slowly my interest awoke.起初我没怎么注意,但逐渐产生了兴趣.