A: When I first came to the city, there were muddy roads everywhere and only a few high-rise buildings.

    B: When did you first come?

    A: After I graduated from university some 20 years ago.

    B: Wow, I had no idea you were so long in the tooth!

    Note: Horses’s teeth, unlike those of humans, continue to grow with age. They also wear down with use, but the changes in the characteristics of the teeth over time make it possible to make a rough estimate of a horse’s age by examining them. The earliest citation is in Thackeray’s “The History of Henry Esmond,” referring to a woman rather than a horse. People also say “Don’t look a gift horse in the mouth,” because it’s impolite trying to figure out the value of the gift.