The phrase "a model appeared" is correct and usable in written English.
It can be used in contexts where you are describing the emergence or introduction of a model, whether in a scientific, artistic, or theoretical discussion.
Example: "During the presentation, a model appeared that illustrated the complex relationship between the variables."
Alternatives: "a model emerged" or "a model was introduced".
A model appeared wearing a black wool blazer with leather lapels, which had a slight shine.
When a model appeared in an abbreviated, stonewashed bluejean jacket, the sleeves of which were slashed and frayed from biceps to wrist, skepticism flickered across Rosen's face.
In a vignette called "the look of lingerie," a model appeared on stage in a red robe as the commentator, dressed in a floor-length sequined gown, cooed into the microphone from her chair on the side of the stage.
Mr. Margiela arranged his show in a series of white-curtained rooms, so when a model appeared in a red dress with a nude illusion top, it was sudden and shocking, as if Wonder Woman's costume had slipped off to reveal a wardrobe malfunction.
It is a model appearing in a fashion show by Junya Watanabe, in the city that barely blinks when presented with apparitions that suggest a sip taken from the wrong goblet and nights that are long and bizarre.
She also worked as a model, appearing in toothpaste ads and fashion adverts in The Tatler, The Lady, The Bystander and The Daily Mirror.
Dresses with harnesses, a chain mail of sequins and a magician making a model appear and disappear in a "magic" box — that is all in a day's world for Manish Arora.
Such a model appears feasible for adoption between other eye centers and eye banks.
Such a model appears in the Appendix: it shows that child time allocation in 2006 has no significant effect on parental health in 2009, and the point estimates of the effects are very close to zero.
Such a model appears consistent with recent research showing that the perception of fear is gated by selective attention at early latencies during exposure, whereas the perception of disgust appears to be modulated by attention allocation at later latencies [9].
In our data such a model appears to be the best of both worlds, correctly accounting for the time-varying effects, while strengthening the results from the constant terms.
