Green is an important color in nature. It is the color of grass and the leaves on trees. It is the color of most growing plants, too.
Sometimes, the word green means young, fresh and growing. Sometimes, it describes something that is not yet finished or plants that are not ripe.
For example, a greenhorn is someone who has no experience, who is new to a situation. In the fifteenth century, a greenhorn was a young cow or ox whose horns had not yet developed. A century or so later, a greenhorn was a soldier who had not yet had any experience in war (战争) .By the eighteenth century, a greenhorn had the meaning it has today——a person who is new in a job.
About one hundred years ago, greenhorn was a popular expression in the American west Old—timers used it to describe a man who had just arrived from one of the big cities in the east. The greenhorn didn't have the skills that he would need to live in the hard, rough country.
Someone who has the ability to grow plants well is said to have a green thumb. The expression comes from the early nineteen hundred.
A person with a green thumb seems to have a magic touch that makes plants grow quickly and well. You might say that the woman next door has a green thumb if her garden continues to grow long after your plants have died.
The Green Revolution (革命) is the name which was given some years ago to the development of new kinds of rice and other grains. The new plants produced much larger crops. The Green Revolution was the result of hard work by agricultural (农业的) scientists who had green thumbs.