来自 then 的拼写变体，并于 18 世纪开始成为两个不同的词，并产生词义上的分化。如 A is bigger than B,原义为 A is bigger,then B.
英文词源
than
than: [OE] Than is ultimately the same word as then, and the two were used interchangeably until the end of the 17th century. It is not clear how the adverb came to be used as a conjunction denoting comparison, although it is possible that the comparison implicit in expressions like ‘This one is better; then there is that one’ may have led on to ‘This one is better than that one’. => then
than (conj.)
Old English þan, conjunctive particle used after a comparative adjective or adverb, from þanne, þænne, þonne "then" (see then). Developed from the adverb then, and not distinguished from it by spelling until c. 1700.
The earliest use is in West Germanic comparative forms introducing the second member, i.e. bigger than (compare Dutch dan, German denn), which suggests a semantic development from the demonstrative sense of then: A is bigger than B, evolving from A is bigger, then ("after that") B. Or the word may trace to Old English þonne "when, when as," such as "When as" B is big, A is more (so).
实用例句
1. Their replies were no more than grunts of acknowledgement.
他们所谓的回答不过是表示承认的咕哝罢了。
来自柯林斯例句
2. She's got a great voice and is singing better than ever.
她的嗓音非常好，现在的唱功比以往任何时候都要好。
来自柯林斯例句
3. The plane has been kept in service far longer than originally intended.
这架飞机已经超期服役很长时间了。
来自柯林斯例句
4. Jovial ladies chivvy you into ordering more than you can eat!
热情的女招待会一再推荐，最后点的餐多到吃不下!
来自柯林斯例句
5. Father had no more than a superficial knowledge of music.