知识扩展
 
English has many "compound" words, that is, words that are made up of two complete words. Take a look at the following:
 
英语中有大量的复合词，其由两个单词结合在一起组成。例如：
 armchair n.扶手椅子 arm + chair
 baseball n.棒球 base + ball
 classmate n.同班同学 class + mate
 evergreen n.常绿植物 ever + green
 breakfast n.早餐 break + fast
 grasshopper n.蝗虫 grass + hopper
 tiptoe n.脚尖，趾尖 tip + toe
 weekend n.周末 week + end
 trademark n.商标 trade + mark
 popcorn  n.爆米花 pop + com