Subtle Hints

Dear Dad, $chool i$ really $well. I am making lot$ of friend$ and $tudying very hard. I have $o much $tuff, I $imply can't think of anything I need. $o if you like, $end me a card, a$ I would love to hear from you. Love Your $on Dear Son, I kNOw astroNOmy, ecoNOmy, and oceaNOgraphy are eNOugh to keep an hoNOrs student busy. Do NOt forget that the pursuit of kNOwledge is a NOble task, and you can't study eNOugh. Love, Dad