A crow（乌鸦） lived in the forest and was very happy with his life.But one day he （1）______ a swan（天鹅）."This swan is so white,"he thought,"and I am so black.This swan must be the happiest bird in the world."
He told his ideas to （2）______ swan.The swan answered,"I was feeling that I was the happiest bird （3）______I saw a parrot,which has two colors.Now I （4）______ the parrot is the happiest bird."The crow then went to the parrot.The parrot said,"I lived a very happy life until I saw a peacock（孔雀）.I have only two （5）______ ,but the peacock has many colors."
The crow then visited a peacock in the zoo and saw that many people （6）______ him.After the people left,the crow went to the peacock."Dear peacock,"the crow said,"you are so （7）______.Every day so many people visit you.But when people see （8）______,they go away at once.I think you are the happiest bird in the world."
The peacock answered,"I （9）______ thought that I was the most beautiful and happiest bird in the world.But because of my beauty,people catch me into this (10)______.I look around the zoo very carefully,and I find that the crow is the only bird not in a cage（笼子）.So I hope that if I were a crow,I could fly everywhere (11)______."
We also have the same (12)______ as the crow.We always compare（比较） (13)______ others and become sad.As a result,this leads to the worst cycle of unhappiness! (14)______ to be happy with what you have is important.If one is (15)______ with himself,he is the happiest in the world.