彼は私より２歳年下だ。
tbd
He's two years younger than I.
He is two years my junior.
He is junior to me by two years.
He's two years younger than me.
He's two years my junior.
他比我小兩歲。
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