【正确答案】Lao Zi makes a great contribution to China's history of traditional thought mainly in three aspects: first of all, he transforms China's traditional thought from the concrete thinking to the abstract creative thinking by putting forward the abstract conception of "Tao" and highlighting the universe unity; secondly, he enriches and develops dialectical thought, making it become a glorious tradition in ancient China's thought; thirdly, he brings forward a mode of reverse thinking, which makes Taoism and Confucianism exist simultaneously and complementarily and grow into two main schools of China's traditional thought.