From then on, I no longer bowed my head but began to smile to my classmates.
This sentence is taken from a China's classroom test paper and the article is clearly written by a Chinese student. I thought we should say 'smile at sb' rather than 'smile to sb'. Am I right?
Thank you very much.
Yes, smile "at classmates" is correct in this sentence.
But you can give a smile to your friend, also.