Are You a Punctuation Master?

Punctuation experts: See whether you can find a variety of punctuation errors sprinkled throughout the business letter below. In some places, punctuation is missing; in others, it's unnecessary or wrong. Find and correct the errors, but do not change the wording.


Dear Professor Donaldson,

Kate Michaels has asked me to write a reference for her in support of her internship application and I am delighted to do so. Kate worked with me from January, 2014 through August, 2015 as a teaching assistant in our marketing program, I was her direct supervisor.

Kate's greatest strengths I have observed include: her creativity, initiative, strategic thinking, and high standards for her work. She used creative approaches to help students' understand complex concepts in marketing statistics. (I confess having learned from her in this area). She took initiative to enhance online outreach to students, showed evidence of a keen understanding of both short term results and long term benefits of various marketing strategies, and consistently delivered professional, high-quality work. Kate was an outstanding teaching assistant.

Kate mentioned that the internship involves marketing research studies. I believe she would be excellent in that area because of her strong analytical skills, however, I have not witnessed her work in that area.

Professor Donaldson if you need any additional information about Kate Michaels please contact me by phone or email. I will leave on a six month sabbatical in a months time, but I am available until then.


Serge Cooper


Did you find all 15 errors planted in the letter? Use this answer key to compare your answers with mine. 

To increase your punctuation mastery, take my online self-study course Punctuation for Professionals. The free trial will help you decide whether it's right for you.

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  1. Hi Dear Lynn

    Speaking of punctuation, could you please tell me about the rule for adding ‘s to the words ending in S like Charles, boss, … . Or is there a page in the website explaining this?



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