1At (used to indicate cost or rate per unit)

30本词典，每本29.99英镑。

1. 1.1informal At (in any sense)
   he dealt fairly well with tough issues thrown @ him

   If you are staying @ a hotel, it will have a laundry service

2Used in Internet addresses between the user's name and the domain name.

1. 2.1 (in an online discussion, especially on the social media application Twitter) preceding the name of a person to whom a comment is directed.
   @Oliver: I'm aware of that fact