Q: Does the word "know" mean the same thing in "I know it's time." and "He knows about 19th century politics."?

A: the same meaning

Q: Does the word "hit" mean the same thing in "One boy hit the other." and "I have to hit the MAC machine before the weekend starts."?

A: different meanings

Q: Does the word "head" mean the same thing in "He stuck his head out the window." and "Be careful when you pet that dog on the head; it may bite."?

A: the same meaning

Q: Does the word "time" mean the same thing in "Okay, but this is the last time. No more after that!" and "He called four times."?

A:
the same meaning