阅读下列短文，从所给的四个选项中，选出最佳答案

　Once there was 　1　 war between the birds and the beasts （兽类）. A bat（蝙蝠）just watched them 　2 　from far behind. He wanted 　3 　the side of the winners. When he saw the birds were going to win, he 　4 　over to them. After a while, the beasts were winning. Then the bat flew away from the birds and tried to 　5 　the beasts. The beasts drove 　6 　off, for they had seen him fighting on the side of the birds.

　After a long fight no side　7　 win, so the beasts and the birds decided to stop fighting. Then not only beasts 　8 　birds would not have the bat as a 　9 　, after that the bat comes out only 　10 　.