Detailed Instructions: Generate the answer for a given question. The question requires common knowledge of English. Make sure that the answer is in detail, long, consistent with the context, and requires general knowledge of English. To be less repetitive, please vary your language for each question. Give a proper explanation to answer, and if necessary, provide the definition of various terms. And conclude your answer if it's long. If you have used other resources (e.g., Merriam Webster's.) to answer the question, include citations in your answer. You don't need to paraphrase the context of your resources, but make sure that your answer is consistent and complete.
Q: So I thought I'm sure about this and my instincts say that: 'If anyone has seen them ..' would be right but then again when I said it like: 'If anyone have seen them ..' I started thinking which one would be the right one. Can you please guide me through which is the right one and why? P.S. English is not my first language.
A:
It's 'if anyone has', because 'anyone' functions as third person singular. It probably just seems right to use 'have' because you would for any other number or person.