at first

Spojení at first/ət 'fɜ:st­//ət 'fә́st//ət 'f­ɜ:rst//ət 'fә́rst/ můžeme přeložit jako zpočátku, ze začátku, nejdříve, nejprve apod. Použijete ho v případě, kdy došlo k nějaké změně. Může stát na začátku i na konci věty (často v souvětí).

The water seemed very cold at first, but she got used to it. ^*1
At first she didn't like him, but then she realized he was a nice guy. ^*2
The job itself was hard work at first, but I got used to it. ^*3
At first it was fun, but after a while it got boring. ^*4
At first her husband denied sleeping with another woman, but then he admitted it. ^*5
No one wanted to help her at first, but one of her colleagues eventually gave her a hand. ^*6
When they moved, his wife was very unhappy at first, but then things started to get better. ^*7
What do you think of the new colleague? – Well, I didn't like him at first. ^*8
At first we thought he was joking. Then it turned out he wasn't. ^*9 

Nemusí stát vždy v souvětí. Můžete říct pouze část se spojením at first. Automaticky je to chápáno tak, že se situace změnila:

At first she didn't like him, but then she realized he was a nice guy. ^*10
At first she didn't like him.
She didn't like him at first.

Spojení at first by se mohlo plést se samotným first (případně se slovem firstly). Je zde však tento rozdíl:

• zpočátku – at first → but then. (změna situace)
• nejprve – first → then … then … next … (sled událostí)
• za prvé – first(ly) → second(ly) … third(ly) … (výčet, seznam)

At first it was fun, but after a while it got boring. ^*11
First I unlocked the door, then I entered. ^*12
Firstly, I'd like to speak about turnover. Secondly, I will mention profit. ^*13 

Více o rozdílech a použití v článku FIRST, FIRSTLY, AT FIRST.