英汉例句双语例句Why doi birds fly south?鸟为什么往南飞?。Why do birds fly south?鸟为什么往南飞?。www.zk168.com.cnWhy do birds fly south for the winter?为什么鸟儿在冬天的时候飞往南方?blog.sina.com.cn原声例句Birds fly south because they know winter is coming.birds fly south更多例句词组短语短语The Birds Fly South 第十六章birds fly south更多词组