彼は彼女より３つ年上です。
tbd
He's three years older than her.
He is older than she is by three years.
He's three years older than she is.
は
1. indicates sentence topic
2. indicates contrast with another option (stated or unstated)
3. adds emphasis
指示句子的主题；表示与另一选项（无论是否明确提及）形成对比；表示强调
より
1. than
2. rather than, instead of, over, above
3. from, out of, since, at, on (and after)
4. except, but, other than
5. more
更，更加