Can someone explain this sentence to me?
What does をあげます, means in the phrase 私はジョンにそのりんごをあげます。?
をあげます means give . 私はジョンにそのりんごをあげます。means i give John the apple. give in this sentence means that John didn't have an apple so you gave John your apple. "I give John the apple"!
"I give John that apple."
あげます means "give", and the particle を marks what is being given (in this case そのりんごを, so "that apple" is being given).
私は (as for me) ジョンに (to John) そのりんごを (that apple) あげます。(give).
So, basically, I give John that apple.
Also, here's a fun bonus fact: あげる also means "to raise" with the implication here being that you're humbly "raising" a gift to someone else. So あげる only applies when you're giving something to someone else. There's a different word for when you describe someone giving something to you.