study in class and out of class
   our study can be divided into two parts: one is in class and the other is out of class. both of them are important to students. they depend on each other.
   we must attach importance to after-class what we have learnt in class is very. limited, because only knowledge in textbooks can be acquired. however, we can learn more out of class. a most important thing is that knowledge comes from practice. in the after- class study we can apply out knowledge to practice.
   just iike after-class study, study in class is also very important. it occupies most of our time. we must pay much attention to it. in-class study and after-class study are closely connected with each other and improve each other.
   if that' s the case, why don't we combine them and study effectively? 
课上课下
   我们的学习可以被分成两部分：一部分在课堂上，另一部分在课堂外。这两部分对学生来说都是重要的，它们互相依存。
   我们必须重视课后学习。我们在课堂上学到的东西是有限的，因为只能学到课本上的知识。然而，课外我们可以学到更多的东西。最重要的是知识来源于实践。课外学习可以让我们把知识应用到实践中去。
   正如课外学习一样，课内学习也很重要。它占用了我们的大部分时间，我们必须重视它。课内与课外的学习紧密地联系在一起，它们互相促进。
   这样的话，我们为什么不把它们结合在一起，有效地学习呢?