While you wait for the broccoli and carrot to cook, mix oyster sauce, soy sauce, and sugar in a separate bowl. Then, pour this mixture over the rest of your vegetables and add some water.
Cover the pan with the lid for about 1 minute, or until the vegetables reach your desired level of tenderness. If you prefer crunchy vegetables, leave them for a few minutes. If you prefer soft vegetables, leave them for a bit longer.