Accept is to allow something. EX- My application was accepted.
Except is to exclude something. EX- He said everything was good except the last part.
Affect is an action, as in something that changes or modifies something else. EX- The sound affected my concentration.
Effect is the result of an action on someone or something. EX- the effect of the sonic boom left me dazed.
Dual means two characteristics that someone or something has. EX- That business is a dual ownership.
Duel is a fight, typically between two participants only that has been prearranged and follows a pre-established set of rules. EX- Sword duelling between gentlemen trying to win the suite of a lady was a common occurrance.
Expand is to increase in size. EX- The balloon expanded until it popped.
Expend is to use up a resource. EX- He expended his energy and became tired.
They're - this is a contraction of the words they are. This is often used to show a group doing an action. EX- They're going to the store.
There - This, typically, is used to indicate position, like if someone were pointing and said “there”.
Their - This is used to show that something belongs to someone. EX- the truck is theirs, it belongs to them.
Then is used to show progression, from one action to the next or from one time to the next. EX- I went home then I got a drink.
Than is used to show comparison. EX- 2 is greater than 1.
Canon is the core plot, characters and world central to one work/series created by one author (or for larger projects like videogames, one group). For example, Dante is a canon character to the Devil May Cry series created by Capcom.
Cannon is a heavy artillery weapon. Originally fired 4-10 pound balls of lead, steel or objects at targets from greater ranges than smaller firearms could hit. Currently a cannon refers to any large weapon (like a .50 Magnum revolver might be called a hand cannon.)