Regular verbs are verbs that form their past tense by adding ed to the end of the verb. Walk becomes walked, dance become danced and so on. Unlike regular verbs, irregular verbs form their past tense by changing their spelling. In other words, they become new words. The following set of short answer exercises present you with a group of irregular verbs along with at only one their forms. It is up to youto enter the other forms in the blanks provided. To check if you have entered the correct word, click the "Check" button. If you get stuck or are not sure of the word to use, click the "Hint" button to get a free letter. There are nine sets of irregular verbs. To move to the nest set in the exercise, click the "More Irregular Verbs" button.