题目

阅读理解；阅读下面四篇语言材料, 然后按文后要求做题。    The aim of students who came to school is to study. But to study requires(需要) a right way,or you waste either the time or the money. The following are the ways of studying.    The best time for reading is morning，because in the morning，the air is fresh and the mind is clear. For that reason，we can get good result.In studying we must have patience(耐心). If we don’t know a text well，we must read it again. We should not read the next one till we have learned the first one.When we are stu 如下图所示，根据通电螺线管的磁感线方向，标出电源a端的正负极、小磁针b端的极性．