Giacomo Giammatteo 
No Mistakes Grammar Bites, Volume IX [EPUB ebook] 
A While and Awhile, and Envy and Jealousy

Guaranteed Not to Be Confusing
Don’t Ever Be Confused by Grammar Again. Take a 'bite’ out of Grammar with No Mistakes Grammar Bites.
It seems as if many dictionaries and books on grammar do their best to confuse people. Words and explanations are defined using grammatical terminology that is difficult to understand; in fact, if you knew that terminology, you probably wouldn’t have to look up the words to begin with.
We’re aiming to get rid of that and explain things in plain English, using language that is easy to understand.
Try it out and see for yourself. If you find these books confusing, write to me and get a refund; they’re guaranteed.