Can you find the error in this Ultimate Grammar Cheat Sheet?

I recently found this grammar cheat sheet at Australian professional editing and proofreading company The Expert Editor and was excited to make use of it (I still will). But I was surprised to find an error. Can you also locate it? Comment below!

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Happy search & find :)

This little "find the error" exercise is not meant to undermine the guide. It is super useful and I hope you bookmark it and put it to use!

I also liked this useful list/guide of common mistakes. Check it out!