What Is This ?/ This Is

Question 1

What is the general rule to say “what is this ?” ?

Answer 1

Use the pronoun “이 가” + “noun” +”이 에 요/예 요”

Question 2

What is the deference between “뭐 예 요 ?” and “이 가 뭐 예 요 ?” ?

Answer 2

The first one means “what it is ?” and the second ones “what is this ?”