There has been an error in the display of this page. There has been an error in the display of the nav on this page. Click on an exercise title to enter the exercise page. Exercise 1: Correcting verb phrases with a missing verb Exercise 2: Fixing verbs that are missing a final -s Exercise 3: When to use an -ed ending Exercise 4: Using the past participle form (-ed/-en) after have or be Exercise 5: Using the base form after modals (could, must) and do Exercise 6: Using infinitives (to act) or gerunds (acting) Exercise 7: Review: Fixing errors with verb forms There has been an error in the display of this page.