Sometimes it’s the small things that reveal to others that we are not yet proficient at English as a second language.
For example:
the conjugation of the verb “do”. I do, you do, we do, and they do…but, it does, he does, and she does. Also, I go, but he goes. They eat but it eats. I understand, but she understands…etc.
It seems like a small thing, but correcting this mistake will improve others ability to understand you, and gain you respect for your excellent English!!