Heat peanut oil in a wok or large skillet over medium-high heat.
Stir in the garlic, and cook until the edges begin to brown, about 20 seconds.
Add the green beans; cook and stir until the green beans begin to soften, about 5 minutes.
Stir in the sugar, oyster sauce, and soy sauce.
Continue cooking and stirring for several minutes until the beans have attained the desired degree of tenderness.