Look at the verbs. Give the second and the third forms. Write them into 2 columns: regular verbs and irregular verbs. список глаголов : discover, sail, be interested (in), appear, prepare, smoke, depend (on), fight, sell.

Regular verbs: discovered - discovered, sailed - sailed, appeared - appeared, prepared - prepared, smoked - smoked, depended - depended (on).

irregular verbs: was interested (in) - been interested (in), fought - fought, sold - sold.