题目

The world is getting warmer. Human activity is the main reason for this, the United Nations （UN） said. For example, people use fossil fuels （化石燃料）like coal and oil. They give off a lot of greenhouse gases （温室气体）（especially CO2） into the air. This warms the earth. As a result, many animals are dying out, （A）________as penguins （企鹅）and polar bears. It will soon make a difference to us as well. （D） Sea levels will rise and many cities along the sea will disappear. To fight climate change, countries around the world need to work together. China is no13．林场栽了125棵杨树，栽的松树比杨树多21棵，栽的柏树的棵数是松树的8倍．柏树栽了多少棵？