重点讲解：
1. come from
来自；始于；
eg. Chocolate comes from the cacao tree.
巧克力出自恒星树。
eg. The term 'claret', used to describe Bordeaux wines, may come from the French word 'clairet'.
用来指称波尔多葡萄酒的词 claret 可能源于法语单词 clairet。
2. originate from
来源；起源；
eg. All carbohydrates originate from plants.
所有的碳水化合物均来自植物。
eg. The rhythms of jazz music originate from African tribal music.
爵士乐的节奏起源于非洲的部落音乐。
3. as far as I know
（用于表示不太确信）据我所知；就我记得的；
eg. It only lasted a couple of years, as far as I know.
据我所知，它仅仅维持了两三年。
eg. So far as I know, she has a faculty of housekeeping.
就我所知，她很善于理家。
