Are You Smarter Than A 9th-Grader?

The numerous required standardized tests for my students often include questions involving what the writer world calls "copy editing" and what teachers call "editing."  In other words, those who want the "data" from these tests hope to see if kids can spot and correct errors in spelling, punctuation, and grammar.
My assignments on this skill are a bit stale, as I created them a good six years ago, and I wanted something new.  So, for the last couple of weeks, I've simply copied and pasted errors I've read and/or heard on the internet and used them to create new assignments.
So, are you smarter than a 9th-grader?  Can you correct any of the following errors I've gathered?  (I'm giving you a greatly-condensed list here.)

Correct The Errors

1. "If I had of gone at 18, I wouldn’t have messed up so much between 18 and 19," Salazar quipped.   -- Donald W. Meyers, reporter for the Salt Lake Tribune. 10/7/12
2. “ ...the drill instructor had a book .... that he found in his muffle bag.”  -- blogger. 10/6/12.
3. “ The real question ...  is what kind of Christians they are?” Peggy Fletcher Stack, reporter for the Salt Lake Tribune.  10/7/12
4. “Contests are earning less entries.”  -- blogger 10/8/12.
5. “We've got to face it- blog-blitz enthusiasm has wained” -- blogger  10/8/12.
6. “If you have a review request that is part of a series, We do ask that you provide a copy of each of it's predecessors.”  -- on a blog with well over 2000 followers. 10/9/12.
7. “Overall though its very simple to use.” -- ditto.
8. “It came in a nice gift-able box that features the unit itself and SodaStream logo's.” -- ditto.
9. “The Winner will win the unit pictured below. You will also get your choice of Red, White or Black for the color of the unit as well as pick 3 regular sized flavorings of your choice.” -- ditto.
10. “Publishers are cutting down their lists, and agents are taking on less clients.” -- blogger, 10/10/12
11.  “After running a mile, a screw came loose in Ben’s prosthetic leg.” -- Melissa Knowles on Trending Now Yahoo!, 10/11/12
12. “He can eat, sleep and do everything other sheeps can." -- author of a Yahoo! article about a malformed sheep, 10/11/12