【简答题】You either have it, or you don’t — a sense (感觉) of direction, that is. But why is it that some people could find their way across the Sahara without a map, while others can lose themselves in the next...
【简答题】判断正(T)误(F)。 (T=True, F = False) What is color? Why do some of the things around us look red, some green, others blue? Colors are really made by reflected (反射) light. We can see colors because most of ...