Please correct

  1. That’s mine. I saw it first.
    1a. That’s mine. I saw it at first.
  2. First, I want to talk to you.
    2a. At first, I want to talk to you.
  3. First they were happy, but then things started going wrong.
    3a. At first they were happy, but then things started going wrong.
  4. Come any time.
    4a. Come at any time.
  5. I am seeing her on Sunday.
    5a. I am seeing her Sunday.
    Please correct the above sentences if they are wrong.
    Thanks.

1 2 3 3a 4 4 5 5a are correct.

Beeesneees,

  1. First I wanted to thank you.
  2. At first I wanted to thank you.
    Are both sentences correct?
    Please comment.
    Thanks.

Hi, Allifhatima:

May I add someting?

In an informal style, we sometimes leave out on before the names of the days of the week.
Why don’t you come for a drink (on) Monday evening?

Similarly, the phrase any time is used mostly in conversational situations.

They are used in different situations and ‘at first’ would only be used if you are indicating that for some reason you no longer wish to thank the person.