Green is an important color in nature. It is the color of grass and the leaves on trees. It is also the color of most growing plants.
Sometimes, the word "green" means young, fresh and growing. For example, a greenhorn is someone who has no experience. In the 15 the century, a greenhorn was a young cow or an ox whose horns (角) had not yet developed. A century later, a greenhorn was a soldier who had no experience in war. By the 18th century, a greenhorn had the meaning it has today—a person who is new in a job.
Someone who is good at growing plants is said to have a green thumb. The expression comes from the early 20 the century. A person with a green thumb can make plants grow quickly and well. The Green Revolution is the name given some years ago to the development of new kinds of rice and other grains. It was the result of hard work by agricultural (农业的) scientists who had green thumbs.
Green is also the color used to describe the powerful feeling jealousy (嫉妒). The green eyed monster isn't a dangerous animal from outer space. It is an expression used about 400 years ago by the British writer William Shakespeare in his play "Othello". It describes the unpleasant (不愉快的) feeling when someone has something he wants.
In most places in the world, a green light is a signal to move ahead. In everyday speech, a green light means approval (赞成) to continue with a project.
