A good memory is certainly very helpful (有帮助的，有益的) for your study. However not everyone has a good memory. Besides, to forget things is not always a bad thing. As a matter of fact, to forget certain things may help you remember more useful and meaningful things.

　　I am sure everyone has this experience, that is, when you have learned something and remembered it, the memory will stay in your mind and you refuse to accept new ideas about it. If you find what you have remembered wrong, it is even more difficult to forget. In this sense, it is easier to remember new things than cast away wrong memories.

　　There are things that you forget permanently (永久地) and things you forget only temporarily (暂时地). For instance (例子), sometimes when you are doing mathematics, you just cannot think of a certain formula (公式). Or sometimes when you come across a friend, his name just escapes you. They are examples of temporary (暂时的) loss of memory. When this happens, you had better try to do something else. And if you return to the maths some time later, you can most probably remember the formula.

　　Needless to say you must try hard to get rid of wrong memories. But sometimes it is also necessary to forget forever things that are correct. For example, we may have watched hundreds of films since childhood (童年). If we remember every film (though this is not highly possible), we will not be able to remember a lot of other things. That is why many films are gradually forgotten as time passes. Yet at the same time, we continue to remember new things. So remembering, forgetting, forgetting, remembering, this is the cycle (循环，自行车，轮转) of our mind.

 69.Getting rid of wrong memories is 　　.

　　as difficult as accepting new ideas　

　　as easy as accepting new ideas　

　　more difficult than remembering new things　

　　much easier than remembering new things　

 70.When you forget something temporarily, you may 　　.

　　think it hard and try to remember it　

　　cast it away and forget it　

　　do some other things and return to it later　

　　put it aside (在旁边) and ask for help　

 71.If you find what you have remembered wrong, you must 　　.

　　keep it in mind　

　　get rid of it　

　　do something else　

　　remember it forever