Simple Stuff (Things you should have learned before high school)
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Then/Than

Quick Tip:
If it tells when, use "then." ​
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Longer Explanation:
  • "Then" is talking about a time, just like "when."  See how they’re spelled?  
    Let's eat first and then go for a run.  [When should we go for a run?]
  • It can also be used with "if":
    If you ask nicely, then I might buy you some ice cream.  [When will you buy me some ice cream?]
  • "Than" is used to compare things:
    She’s older than I am.  [comparing her and me]
Click on the button to do the exercise.  It doesn't count until you get 90%, so keep trying until you do.  Be sure to get a screenshot of the results.

Who/Whom

Quick Tip:
Think about "he or him" and listen for the 'm' sound.
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Longer Explanation:
  • If it’s a question, answer it with he or him.
    Did you see who/whom picked up my notebook?
    He picked it up. ➜ ​Did you see who picked up my notebook?
  • If it’s not a question, ignore the first half and substitute he or him in the sentence.
    I'm not sure who/whom I'm going to vote for.
    I'm going to vote for him. ➜ I'm not sure whomI'm going to vote for.
Click on the button to do the exercise.  It doesn't count until you get 90%, so keep trying until you do.  Be sure to get a screenshot of the results.

It's/Its

Quick Tip:
Try to say "it is" or "it has" in the blank.
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Longer Explanation:
  • "It's" has two meanings: "It is..." and "It has..."
    It's going to be a great day.  [It is going...]
    It's been fun, but I have to go.  [It has been fun...]​
  • "Its" shows that something belongs to 'it' (e.g., your dog), just like his, hers, yours, etc.  Do you see how they all end with the s sound but DON'T have an apostrophe?
    He got a new truck, and he's really proud of how its engine sounds.
    My dog can never find its toys after he buries them in the yard.
Click on the button to do the exercise.  It doesn't count until you get 90%, so keep trying until you do.  Be sure to get a screenshot of the results.

Who's/Whose

Quick Tip:
Try to say "who is" or "who has" in the blank.
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Longer Explanation:
  • Just like "it's," "who's" has two meanings: "Who is..." and "Who has..."
    Who's going to the game tonight?  [Who is going...]
    Who's been using my laptop?  [Who has been using...]​
  • "Whose" shows that something belongs to someone, just like his, hers, yours, & its.  Do you see how they all end with the s sound but DON'T have an apostrophe?
    I'm not sure whose bag this is.
    Whose room are you going to be in for Seminar today?
Click on the button to do the exercise.  It doesn't count until you get 90%, so keep trying until you do.  Be sure to get a screenshot of the results.

Sit/Set & Raise/Rise

Quick Tip:
"Set" and "raise" have to have a thing (a direct object).  
​"Sit" and "rise" don't.
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Longer Explanation:
  • "Set" and "raise" are things you do to someone or something.  There has to be an object.  ​They're called  'transitive' verbs.
    Set that book down.
    Raise your hand.  [You're doing something to your hand.]
  • "Sit" and "rise" are things you do yourself.  They're called  'intransitive' verbs.
    I need to sit down.
    Your grade won't rise on its own.
Click on the button to do the exercise.  It doesn't count until you get 90%, so keep trying until you do.  Be sure to get a screenshot of the results.

Lay/Lie

Quick Tip:
"Lay" needs a thing (a direct object), just like "set" and "raise."  It might help to remember this rhyme:
You SAY something.  You LAY something.
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Longer Explanation:
  • "Lay" is what you do to something else:
    "Lay your book down."  [The book doesn’t lay itself down, right?]
  • "Lie" is something you do yourself, (like "sit" and "rise").  Notice they all have an "i" in the middle.
    You sit down, and you lie down.  
  • If you say "I’m going to go lay down," I'll ask you "Really, are you going to lay an egg or what?"  You have to lay down a thing.
Click on the button to do the exercise.  It doesn't count until you get 90%, so keep trying until you do.  Be sure to get a screenshot of the results.

Possessives

Quick Tip:
Singular?  Use 's. 
Plural AND already ends with s?  Just add '.
Plural but no s?  Use 's.
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Longer Explanation:
  • If the word is singular, add 's.
    sister's friend (one sister)
    table's legs (one table -- it doesn't matter how many legs)
  • If the word is plural AND ends with s, just add an apostrophe.
    dogs' (more than one dog)
  • If the word is plural but DOESN'T end with s, add 's.
    women's (more than one woman)
  • For names of famous teachers & philosophers (Jesus, Moses, Socrates, etc.), just add an apostrophe.
    Moses' people
Click on the button to do the exercise.  It doesn't count until you get 90%, so keep trying until you do.  Be sure to get a screenshot of the results.