Can you please check this for any grammatical errors?

Thank you for your help.

Having been out of school for 15 years, I seem to have forgotten the fundamentals of grammar. Taking Composition and Communication 155 has helped me gain a better understanding of basic grammar and the importance behind it, making me feel more confident in my writing.

I have always had trouble determining why or when a comma or an apostrophe needs to be placed. After reading Chapter 37 & 38, I learned that commas are very important because they help readers understand the sentence. Apostrophes are used to show ownership, or replace a letter to form a contraction. Learning where and when to correctly place commas and apostrophes has not only made my writing clearer to follow; it has also made it more interesting. I am more confident writing emails and short letters to my superiors now, knowing that I have these basic rules down.

Chapter 22 explains the four most serious errors in writing. Before taking this class I was guilty of many of these. I would have run-on sentences in my writing because I was sure I would put the comma in the wrong spot. Fragmented sentences were also a problem for me; I would have sentences that should be combined throughout my writing. Now that I know a sentence must include a subject, verb, and a complete thought, I should not have this issue any longer.

This class has taught me a lot in these last four weeks. I know I still have a long way to go to become a “good” writer, but what I have learned, has made me feel more confident in my writing than I ever have.

4 answers

Your composition is good. I see no errors, and I think it's wonderful that you put the semicolon in the right place in the second paragraph. Congrats!
In this sentence, I'd use a comma rather than a semicolon after "follow." If you omit "not only," the semicolon would be correct.

Learning where and when to correctly place commas and apostrophes has not only made my writing clearer to follow; it has also made it more interesting.
If you want to use a comma, then you need the complete correlative conjunction set: ... not only ... but also ...

http://grammar.ccc.commnet.edu/grammar/conjunctions.htm#correlative_conjunctions
Review Ch. 2, Section 6 of the text. Describe your experience with credit and credit cards in a brief paragraph using at least five adverbs and five adjectives in your description. Bold the adverbs and underline the adjectives. What is the most effective way to determine whether a word is an adjective or an adverb