Thinly slice steak crosswise into 1-by-3 inch strips. Mix with pepper, garlic, and worcestershire sauce, let stand 15 minutes. Place a frying pan over high heat - when pan is hot add 2 tablespoons oil and half of meat. Stir-fry until meat is lightly browned, 1-2 minutes, remove from pan & cook remaining meat (fry separately so that cooks quickly). Remove from pan. Add 1 tablespoon oil, onions, red & green bell peppers, stir-fry until tender/crisp, 2-3 minutes. Stir in meat with its juice, salt to taste.