Question

Mr. Smith is their/theis teacher

Answer 1

Если я правильно поняла вопрос,то their teacher

Answer 2

Mr Smith is their teacher. Слова theis нет.

Answer 3

Mr. Smith is their teacher

Based on the given statement, "Mr. Smith is their teacher," it can be inferred that Mr. Smith is the teacher of a particular group of individuals. However, without additional context, it is difficult to determine who "their" refers to. It could be a group of students, colleagues, or any other group of individuals.

To provide a more accurate response, please provide more information or clarify the context in which the statement is being made.