English words don't stay the same. People need new words for new ideas and new inventions. Different words come into use, or old words are used in a new way.
English can be changed by borrowing words from other languages. The word "tomato" was borrowed from Mexico and "tea"came from China and so on. Now new space and science words are being borrowed from other countries, too. New words are formed by adding two words together. "Countryside" and "earthquake" are made up of two parts. Sometimes new words are shorter forms of old words. The word "photo" was made from "photograph" by cutting off the end of the longer word. "Plane" was made by cutting off the front part of "airplane". The names of people and products can become new words, too. Our "sandwich" was named after a man called Sandwich and "sello tape"(透明胶带) was a name given by the company that first made the product.
