sentence 1: How do I know if I'm good?
 sentence 2: How do I know what I'm good at? sentence 1: How many years does it take to become a CA?
 sentence 2: How many years does it take to do an MS? sentence 1: How can I work at the UN?
 sentence 2: How can I work for the UN?
not same meaning
not same meaning
not same meaning