"PRINCIPAL" and "PRINCIPLE"
"Principal" refers to a person in a position of authority or the primary part of something. "Principle" means a fundamental rule or belief. Ex.: The school principal addressed the students. The principal reason for our success is teamwork. Honesty is an important principle to uphold.
"PRECEDE" and "PROCEED"
"Precede" means to come before in time or order. "Proceed" means to continue or move forward. Ex.: The introduction precedes the main text. After the break, we will proceed with the meeting.