I'm having trouble rewriting the ambiguous sentences. I have answered them but i'm not sure that they are right.

2. Please close the door behind you.
My answer: Please close the door that is behind you.

3. we heard that he informed you of what he said in his letter.
My answer: We understand that he has written a letter, and that he has told you about the contents of the letter.

5. Charles drew his gun.
My answer: Charles took out his gun.

9. Tuxedos Cut Ridiculously!
My answer: Prices on our tuxedos have been drastically reduced.

15. Don’t freeze your can at the game.
My answer: don't throw your can at the game?

21. We’re going to look at lots this afternoon.
My answer: We are going to look at a lot of things this afternoon.

24. New york’s first commercial human sperm-bank opened Friday with semen samples from 18 men frozen in a stainless steel tank.
My answer: New York's first Commercial sperm-bank opened Friday. 18 men gave semen samples, which were frozen in a stainless steel tank.

27. Abraham Lincoln wrote the Gettysburg address while traveling from Washington to Gettysburg on the back of an envelope.
My answer: While traveling from Washington to Gettysburg Abraham Lincoln wrote the Gettysburg address on the back of a envelope.

29. In one of Shakespeare’s famous play’s, Hamlet relieves himself in a long soliloquy.
My answer Hamlet calms himself by reciting a soliloguy.

38. Please do not feed the animals. If you had any suitable food, give it to the guard on duty.
My answer: Instead of feeding the animals give any suitable food you may have brought to the guard on duty.

2. Please close the door behind you.

My answer: Please close the door that is behind you.
I'd write: Please close the door after you leave. (or "after you come in."

3. we heard that he informed you of what he said in his letter.
My answer: We understand that he has written a letter, and that he has told you about the contents of the letter.
Wordy! I'd write this: We heard he told you about the contents of his letter.

5. Charles drew his gun.
My answer: Charles took out his gun.
I agree.

9. Tuxedos Cut Ridiculously!
My answer: Prices on our tuxedos have been drastically reduced.
I agree.

15. Don’t freeze your can at the game.
My answer: don't throw your can at the game?
I would write this: Don't freeze while sitting and watching the game. ["can" is often slang for "your bottom"!!]

21. We’re going to look at lots this afternoon.
My answer: We are going to look at a lot of things this afternoon.
I'd write this: We are going to look at several pieces of property this afternoon. ["lots" = land]

24. New york’s first commercial human sperm-bank opened Friday with semen samples from 18 men frozen in a stainless steel tank.
My answer: New York's first Commercial sperm-bank opened Friday. 18 men gave semen samples, which were frozen in a stainless steel tank.
I'd write this: New York's first commercial sperm-bank opened Friday. Eighteen men gave semen samples, which were frozen in a stainless steel tank.

27. Abraham Lincoln wrote the Gettysburg address while traveling from Washington to Gettysburg on the back of an envelope.
My answer: While traveling from Washington to Gettysburg Abraham Lincoln wrote the Gettysburg address on the back of a envelope.
I'd write this: While traveling from Washington to Gettysburg, Abraham Lincoln wrote ...

29. In one of Shakespeare’s famous play’s, Hamlet relieves himself in a long soliloquy.
My answer Hamlet calms himself by reciting a soliloguy.
I agree with "calms" as a good substitute for "relieves"!!!

38. Please do not feed the animals. If you had any suitable food, give it to the guard on duty.
My answer: Instead of feeding the animals give any suitable food you may have brought to the guard on duty.
I'd write this: Instead of feeding the animals, please give the guard any suitable food you may have brought.

Thank you, I think that I was being to wordy with my answers.

Sometimes we get that way ... then it takes someone else to help us weed out the extraneous stuff!

You're welcome!

2. My answer: Please close the door after you've entered.

3. My answer: We heard that he informed you about what he wrote in his letter.

5. My answer: Charles brandished his gun.

9. My answer: Tuxedos are ridiculously cut!

15. My answer: Don't freeze your butt off at the game.

21. My answer: We're going to look at many properties this afternoon.

24. My answer: New York's first commercial sperm bank opened on Friday, freezing semen samples from 18 men in a stainless steel tank.

27. My answer: Abraham Lincoln wrote the Gettysburg Address on the back of an envelope while traveling from Washington to Gettysburg.

29. My answer: In one of Shakespeare's famous plays, Hamlet shares his inner thoughts in a long soliloquy.

38. My answer: Please refrain from feeding the animals. If you have any suitable food, kindly give it to the guard on duty.

2. Please close the door behind you.

Rewritten: Please make sure to close the door located behind you.

3. We heard that he informed you of what he said in his letter.
Rewritten: We were informed that he shared with you the content of his letter.

5. Charles drew his gun.
Rewritten: Charles pulled out his gun.

9. Tuxedos Cut Ridiculously!
Rewritten: The prices of our tuxedos have been drastically reduced.

15. Don’t freeze your can at the game.
Rewritten: Don't get too cold at the game.

21. We’re going to look at lots this afternoon.
Rewritten: This afternoon, we'll be looking at several things.

24. New York’s first commercial human sperm-bank opened Friday with semen samples from 18 men frozen in a stainless steel tank.
Rewritten: On Friday, New York's first commercial human sperm-bank opened. It stored frozen semen samples from 18 men in a stainless steel tank.

27. Abraham Lincoln wrote the Gettysburg address while traveling from Washington to Gettysburg on the back of an envelope.
Rewritten: While traveling from Washington to Gettysburg, Abraham Lincoln wrote the Gettysburg address on the back of an envelope.

29. In one of Shakespeare’s famous play’s, Hamlet relieves himself in a long soliloquy.
Rewritten: In one of Shakespeare’s famous plays, Hamlet finds solace in a long soliloquy.

38. Please do not feed the animals. If you have any suitable food, give it to the guard on duty.
Rewritten: Please refrain from feeding the animals. In case you have any appropriate food, kindly hand it over to the guard on duty.