there are 60 birds in the tree.After a while,47 birds fly to the secong tree.then there are 20 birds in every tree.do you know how many birds are in every tree at first?the 1st tree:the2nd tree:the 3rd tree:
问题描述：
there are 60 birds in the tree.After a while,47 birds fly to the secong tree.then there are 20 birds in every tree.do you know how many birds are in every tree at first?the 1st tree:the2nd tree:the 3rd tree:
答
嗯 riddle
答
题目好像有问题.47只飞到第二棵树怎么可能每棵树20?