Language point

Age usually refers to the number of years that a person has lived. The following examples show some of the ways of referring to someone's age.

1. My mother is 40 years old.

2. My mother is a 40-year-old school teacher.

(Note: not 'a 40-years-old school teacher'. Also note that '40-year-old' here is a compound adjective, which we discussed on Tuesday.)

3. She teaches six-year-olds.

(Here, 'six-year-olds' is a noun. Remember to use hyphens to make it one unit.)