sentence 1: How do I know if I'm good?
 sentence 2: How do I know what I'm good at? sentence 1: Which triggers a stronger nostalgic feeling: taste, sound or smell?
 sentence 2: Why do we feel nostalgic? sentence 1: How can I see who viewed my instagram post?
 sentence 2: Can someone see if you have viewed public Instagram?
not same meaning
not same meaning
same meaning