We're going to spend one more week talking about basic sentence construction. I know that seems easy, but they always ask grammar questions on the GED, and you'd be surprised how tricky it can be. I know plenty of educated, successful people who make small mistakes in their sentences all the time. I do too! I guess that shows that small mistakes are OK in day-to-day writing, but not on the GED test!
Here are some videos and quizzes from Khan Academy for extra practice. If you haven't already, I'd highly recommend you sign up for Khan Academy. It's totally free, and their lessons are pretty good.