尤其是早晨，它们雀跃着，欢唱着，合奏出一支动听的晨曲，一时间整个校园成了鸟的世界。
O O O B-Time I-Time O B-Thing I-Thing O O O O O O O O O O O O O O O O B-Thing I-Thing O B-Time I-Time I-Time O O B-Location I-Location O O B-Thing O B-Location B-Thing O