本文说的thirteen -year-old的意思是“十三岁大的”，其中的thirteen只是小编随意举的一个例子，它也可换成one, two, three, four, five, six, seven, eight, nine, eleven, twelve等；同时，其中的year也可根据情况改用month, day等词。
一、基本用法
1.用作形容词（一般作定语）
My four-year-old daughter was asleep on the sofa. 我四岁的女儿在沙发上睡着了。
Mary drove. Her ten-year-old daughter sat behind. 玛丽开车，她十岁的女儿坐在后面。
Their five-year-old son is able to use the calendar to count how many days it is until his birthday. 他们五岁的儿子能用日历数出离他的生日还有多少天。
In the car accident the mother was killed, but her two-year-old son was found alive. 在这次车祸中，母亲死了，但是她两岁的儿子却还活着。
2.用作名词（一般作主语或宾语）
A seven-year-old should be able to read. 七岁的儿童应当识字了。
She’s quite clever for a thirteen -year-old. 对一个13岁的孩子来说，她算相当聪明了。
Tim has an average vocabulary for a 3-year-old. 蒂姆掌握了相当于3岁孩子的平均词汇(量)。
二、用提问法掌握词汇用法
1. thirteen-year-old中的year可用复数吗?
不可以。thirteen-year-old这类结构中的year只能用单数，不能用复数。如：
她的两岁的儿子摇摇摆摆地走进屋里。
误：Her two-years-old son toddled into the room.
正：Her two-year-old son toddled into the room.
注：toddle [ˈtɑ:dl] vi.散步;蹒跚行走;（幼儿等）东倒西歪地走;<口>溜达
2. thirteen-year-old中的连字符可以去掉吗?
不可以。若去掉，则要转换表达方式。如：
She has a thirteen-year-old son. 她有个10岁的儿子。
She has a son thirteen years old. 她有个10岁的儿子。
Her son is thirteen years old. 她儿子10岁。
3. thirteen-year-old可用作表语吗？
不可以。若要用作表语，可考虑改用five years old之类的表达。如：
她20岁，但却嫁了一个50岁的丈夫。
误：She was twenty-year-old, but married a man of fifty.
正：She was twenty years old, but married a man of fifty.
4. thirteen-year-old前用a还是an？
five-year-old前若需要用不定冠词，要用a，不能用an。但是，若将其中的thirteen改为eight, eleven, eighteen, eighty等，则其前要用an，不用a——尤其是当它们以8, 11, 18, 80这样的数字出现时更要引起注意。如：
He has an 11-year-old daughter. 他有一个11岁大的女儿。
He married an 18-year-old American girl. 他娶了一个18岁的美国女孩。
5. thirteen-year-old用作名词时可以有复数形式吗？
可以。thirteen-year-old这类结构用作名词时，若语法上需要用复数，可以在词尾加-s。如：
Eighteen-year-olds qualify to vote. 年满十八岁者有选举权。
注：qualify [ˈkwɒlɪfaɪ] vt.& vi.（使）具有资格;有权;达标
vt.限定，修饰;描述，形容;使合适;证明…合格
vi.合格或成为合格;取得…的资格
The report attacks the idea of exams for 7- and 8-year-olds. 这份报道抨击了对七八岁孩子进行考试的设想。
Even ten-year-olds have started wearing lipstick and make-up in imitation of the older girls. 甚至连10来岁的女孩子们也开始模仿年龄大一点的女孩子开始抹口红和化妆。
注：lipstick英 [ˈlɪpstɪk] 美 [ˈlɪpˌstɪk]
n.口红;唇膏 vt.涂口红于vi.涂口红
复数： lipsticks
imitation [ˌɪmɪˈteɪʃn] n. 仿制品;模仿，仿效;赝品;[生]拟态
adj. 仿制的;人造的
