替代词是用来代替名词的词语。常见的替代词包括 one, ones, that, those 等。这些替代词可以用来避免重复使用名词，使句子更加简洁明了。
one/ ones : that/those 的替代原则:
- one 替代同类、泛指、单数、可数名词(表 人/物)
- ones 替代同类、泛指、复数、可数名词(表 人/物)
- that 替代同类、特指、单数、可数/不可数名词(只能指物)
- those 替代同类、特指、复数、可数名词(表 人/物)
另外，英语中还有两个常见的替代词：one 和 ones。这两个词都是指代名词的单数或复数形式的。例如：
- I need a pen. Do you have one? (我需要一支笔。你有一支吗？)
- I like these shoes. Can I try on ones in my size? (我喜欢这些鞋子。我能试穿一双我的尺码吗？)
- The bridge built of stone is stronger than that built of wood. (石桥比木桥坚固。)
- His younger brother seems to be cleverer than his elder one. (他弟弟似乎比他哥哥聪明。)
- The girls in our class are more active than those in your class. (我们班的女生比你们班的女生活跃。)
- Wise people are more easily respected than foolish ones. (聪明的人比愚蠢的人更容易受到尊重。)
- The light of the sun is much greater than that of the moon. (太阳的光比月亮的光强得多。)
- The culture and customs of America are like those of Canada. (美国的文化和习俗与加拿大相似。)