鸽子

Pigeons and pollution are both common blights in cities around the world, but a group of engineers in London are hoping the birds can help them tackle problems with air quality.对世界上许多城市来说，鸽子和污染问题都是常

passengerpigeon（候鸽）若直接告诉您，stool pigeon（字面意：凳子上的鸽子）指的是“警察的眼线”，似乎太突兀。若追根溯源，寻求“凳子上的鸽子”和“眼线”间的联系，却着实会令你我心痛。重温血淋淋的物种灭绝史，“stool pigeon”