Heat a skillet to medium/hot heat and add the olive oil, beef strips, and garlic. Saute for 5 minutes.
Add the sliced bell peppers, sliced onions, sugar, black pepper, salt, and soy sauce. Saute for 3-5 minutes or until the onions and beef are cooked. Be sure not to overcook the meat because it will become chewy when overcooked. Serve warm on rice or separate.