他今年十岁了的英语是He is ten years old this year。
Years：n.年；日历年；一年时间；与某事相关的一年；年度。year的复数。
Old：adj.古老的；老的；具体年龄；(多少)岁；年纪；年纪大的；不年轻的；老年人。
1、He is ten years old.
他十岁了。
2、lt is his birthday; he is just ten years old.
今天是他生日，他正好10岁。
3、He is either nine or ten years old.
他介于九到十岁之间。
4、He is ten./ He is ten years old.
他十岁。
5、l'd say he was 25 to 30 years old.
我猜他在25至30岁之间。
6、He was barely 20 years old and already running his own company.
他只有20岁，却已经营起自己的公司了。
7、l was twenty years old and ready for anything.
我当时二十岁，什么都愿意去做。
关于年龄的表达：
1、表示“整岁”，直接用基数词或year，age，例如“他20岁”可表示为：He is twenty．
He is twenty years old．
2、表示“在某人几十多岁”，用“in one's ＋基数词复数形式”，例如：他七十多岁。He is in his seventies．她五十多岁。She is in her fifties．
3、表示“快满多少岁”用进行时或将来时，例如“他快满十八岁了”可说成：He is getting on for eighteen．He is going on eighteen years old．
4、表示“差多久满多少岁”用介词off，例如：他差5个月就满19岁了。He is five months off nineteen．她再过3年就50岁了。She is three years off fifty．