Despite having a brain no bigger than the tip of your index finger, pigeons have a very impressive visual memory.
2017年12月四级真题（第一套）阅读 Section A
pigeons are often seen as dirty birds and an urban nuisance but they are just the latest in a long line of animals that have been found to have abilities to help humans.
2017年12月四级真题（第一套）阅读 Section A
柯林斯高阶英汉双解学习词典释义
N-COUNT
鸽子
A pigeon is a bird, usually grey in colour, which has a fat body. Pigeons often live in towns.