Correct Grammar Usage of ‘At’

A preposition is a relationship word, or “connector.” It’s the sort of word that can explain the place, time, or relationship of a sentence and link the words together. In the case of the preposition at, it expresses a specific location, time or position. For example:

• Joe is waiting at home. (location — where is Joe waiting?)

• The appointment is at 9 P.M. (time — when is the appointment?)

• The progress meter is at 75 percent. (position — where is the progress meter?)

Notice that the preposition at modifies the subject of the sentence (Joe, the appointment, the progress meter). Each time, at is also followed by a noun, known as the object of the preposition (home, 9 P.M., 75 percent).