Analysis of test questions: "A cup full of water can't hold more water, but it can only empty the water in the cup." This material shows that the development of things is a process from quantitative change to qualitative change, but this is not the end of the development of things, and things will produce new quantitative changes on the basis of new qualitative changes. So choosing D means that we should have a new starting point and accumulate new quantities. Choose D. A to emphasize the connection between phenomenon and essence; B emphasizing the exertion of subjective initiative; Emphasize the importance of practice.