Algebra’s my favorite class.
Correct
You’ll need to help me.
Correct
Six duck’s swam away.
Incorrect
I love apple’s and blueberries.
Incorrect
The dog’s fur is white.
Correct
I like shades of blue’s and gray’s.
Incorrect
Luke’s bank was full of pennies.
Correct
I will need to grade these paper’s quickly.
Incorrect
She’s alway late.
Correct
The keys’ were lost again.
Incorrect
Donald’s mom is a nurse.
Correct
Diane’s my new friend.
Correct