题目

When my students ask me why I live in a tiny house, they ask it in light of all the “sacrifices(牺牲)”I an making. They know that I have moved from a large apartment in the city to a small custom-built home on wheels in the backyard woods. They know I forego running water, Internet connection, sewage(下水道), and reliable phone reception. However, it was possible for me to be truly happy while living with very few material things. My body responded well, in health, fitness and mood, to a schedule more consistent(一致的)with the natural day and night cycle. Observing the daily甲、乙、丙三个轻质小球，任意两个靠近均相互吸引，已知甲带正电，则乙球不可能带正电带正电；若丙球能吸引不带电的轻小物体，则乙球一定不带电不带电（选填“带正电”“带负电”或“不带电”）