This is the first of two 8-page units devoted to truly essential spelling and usage for secondary students. The download includes a 2-page handout listing approximately 50 frequently misspelled or misused words, such as allowed/aloud, it's/its, whether/weather, your/you're, etc. Each word is accompanied by a sentence illustrating the word in context. This download also includes one practice exam and two entirely unique versions of a spelling/usage test drawing from these words and pairings. Each test is comprised of 40 sentences read aloud to students, who must fill in each blank with the appropriately spelled usage of the word. I've used these tests as essential assessments, accepting nothing less than 100-percent mastery to pass the exam, and I require students to retake versions of the test during office hours or lunch until passing; you could use this method or adapt it for your students' capabilities. NOTE: In 10 years of requiring mastery of this test, from 7th-12th grade, I've observed that every student is capable of mastery...once studying takes place. The blanks on each test form on fairly easy to decipher from the list, but contact me if you get stumped when creating your key. SEE FREE DOWNLOAD FOR PART OF THIS LIST. Please check out my other materials for grammar and mechanics, literary units, and writing instruction.