People are most useful: making money/spending money/opening a restaurant/building a house/driving a car/driving a train/flying a plane/having children/copying/printing/operating a computer/making pictures/creating literature/planting trees/beautifying the environment/making phone calls/keeping cats/cooking/washing clothes/boiling water/mopping the floor/feeding children/caring for the elderly/doing foot massage/beauty/editing. Thesis defense/thesis writing/educating children/writing in Chinese calligraphy/playing the piano/making bread/cutting cucumbers/texting/watching TV/chatting/dreaming/falling in love/doing homework/making friends/talking/going to Baidu/answering questions.