Doubling Before a Suffix

Why does "preferred" double its "r" when "offered" doesn't? Why is it "controlled" with two l's? This one trips up almost everyone, because the answer depends on a rule most people were never clearly taught. The good news is that it's a genuinely useful rule, and once it clicks, a whole family of words falls into place at once. This advanced focus drill is built around that single pattern, so you can master it properly instead of guessing word by word. You'll hear each word and choose the correct spelling, with explanations that spell out the rule and show you exactly how it applies each time.

Here's the pattern at the heart of the drill: when a word is stressed on its final syllable and ends in one vowel followed by one consonant, you double that consonant before adding an ending like "-ed" or "-ing." That's why it's preferred, controlled, equipped, regretted, occurring, admitted, omitted, submitted, propelled, and patrolled. Learn it once and you can apply it to countless words beyond this list, which is what makes this drill such a strong investment. Because it's a more advanced topic, it lives off the main path, ready for when you've handled the everyday words and want to level up. These doubled forms show up constantly in past-tense verbs and "-ing" forms, so getting the rule down sharpens a huge slice of your writing in one go. Take the drill and turn a confusing rule into second nature. Once the rule clicks, you'll start spotting it everywhere, catching words you used to second-guess and spelling them right on the first try. That's the real prize here: not ten memorized words, but a pattern you can carry into thousands of them.