This is the 196th most frequent Korean word.
보다
"보다" means "to see," "to look," or "to watch."
Here '보다' is used as a comparative particle, meaning 'than', to compare the subject 'I' and 'friend'.
저는 친구보다 빨리 달릴 수 있어요.
I can run faster than my friend.
In this sentence, '보다' is used as a verb meaning 'to watch'.
이 영화를 보는 중이에요.
I am watching this movie.
Here, '보' in the compound '생각해 보세요' serves as part of an expression meaning 'to try doing something' and implies giving it a try.