年龄表示法
句型［主语+be+数词（限制语）+years old/years of age］
1. "How old is he?" - "he is just fifty (years old)." (= He is aged just fifty/ His age is just fifty.)
2. "What is his age?" - "He is towards fifty years of age."
3. "Of what age is your son?" - "(My son) eleven and a half years old."
4. "Guess how old Mary is." - "She is about between eighteen and twenty years of age."
5. The little one was five months old. 6. "How old is the moon?" - "She is fifteen days old."
7. "How old is the tree?" - "This tree is centuries old."
8. "How old is the horse?" - "The horse is over four years old
句型［…at the age of+数词］/ ［…at +数字+(years of age)］
1. At the age of sixteen Darwin went to Edinburgh to study medicine and three years later to Cambridge.
2. He died at the ripe age of eighty.
3. She became plump at forty.
4. He graduated at twenty years of age.
5. Children enter school at the age of five, don't they?
句型［…of+数词+years old (或of age)］［…aged+数字+years］［…数字+years of age］
［…in one's+数词复数］
1. He is a boy of eleven years old.
2. My elder brother is a man aged fifty years old.
3. They are all children under five years of age.
4. Children under 10 year of age are admitted at half price.
5. He is a young, gallant officer in his twenties.
6. The granny speaks as if she were a girl in her teens.