The SAT Critical Reading section consists of questions that essentially evaluate a student’s English language command.
Likewise, the ACT’s English section tests a student’s knowledge of the English language: it’s structure and correct usage.
To score well here, the student needs to be strong in grammar. You likely haven’t studied grammar in a while. American schooling, when it hits the high school years, tends to focus more on literature and writing and away from grammar. Literature is, of course, important. But since the SAT’s Sentence and Paragraph Improvement sections and especially the ACT’s English section revert back to middle school grammar, it’s time for a grammar review.