Language/English/Vocabulary/At-first-and-first

"At first" and "first"

Beginning of a situation

We use "at first" to talk about the beginning of a situation, to make a contrast with something different that happens/happened later. "At first". . . is often followed by but. 

Examples:

• At first they were very happy, but then things started going wrong.

• The work was hard at first, but I got used to it.

In other cases

In other cases, we usually prefer first. 

Examples:

• That's mine - I saw it first! (not . . .I saw it at first.)

• We lived there when we were first married. (= . . . in the early days of our marriage.) (not . . . when we were at first married.)

• First, I want to talk about the history of the problem. Second, I'll outline the situation today. Third, we'll discuss possible solutions. (not... At first, I want to talk . . .)

"First" in the last example is usage in American English. In British English, this example would be expressed as:

• Firstly, I want to talk about the history of the problem. Secondly, I'll outline the situation today. Thirdly, we'll discuss possible solutions.