冠詞是指那小而美的三個字：a, an, the。其中 'a' 與 'an' 又稱為不定冠詞，'the' 稱為定冠詞。
不定冠詞 'a/an' 後面跟著未明確指出的單數可數名詞。
定冠詞 'the' 後面跟著明確指出或先前已提過的單數或複數可數名詞、或不可數名詞。
A boy and some girls are in the playground.
The boy is playing basketball, but the girls aren't.
If I were you, I would go to see a doctor.
If I were you, I would go to see the doctor.
Everyone who works in this laboratory uses a computer.
Everyone who works in this laboratory uses the computer.
The money was from her paycheck.
- The chicken laid egg.
- Please hand me book; any book will do.
- My brother enjoyed book you gave him.
- Where is bathroom?
- Are you sure this is man who stole her car?
- Somebody call policeman!
She is a friend of mine.
I have a dog and two cats.
He took an umbrella for fear of being caught in the rain.
Any idiot can figure that one out.
- The honesty is not necessarily the best policy.
- Honesty is not necessarily the best policy.
- She is student.
- She is a student.
- Mr. Chen is lawyer.
- Mr. Chen is a lawyer.
- I play a tennis every Saturday.
- I play tennis every Saturday.
- I go to a church every Sunday.
- I go to church every Sunday.
- There is church on the corner of the street.
- There is a church on the corner of the street.
A number of 與 The number of
雖然 "a number of" 與 "the number of" 裡的介系詞 of 後面的受詞通常都是用複數名詞，但是 a number of 後面用複數動詞，而 the number of 後面用單數動詞。
|a number of
A number of studies have found that just being around a dog or petting a dog can lower blood pressure.
A number of schools were closed when the city was hit by the storm.
|the number of
The number of students in this class is 15.
The number of stores in the city has tripled since 2008.
the number of 與 a number of
|A number of ants are swarming into the kitchen.
|The number of ants in the kitchen is increasing.
A percentage of 與 The percentage of
The percentage of obese kids has risen.
量詞 "a percentage of"， 使用單數動詞或複數動詞取決於 of 後面的名詞。
A large percentage of the older population is voting against him.
In Chicago, rent as a percentage of income has risen to 31 percent.
In many of the highest-paying professions, women's salaries as a percentage of men's are lowest.