You use 。。。
You use 。。。。
a
例子 A or an
A or an is the indefinite article. It is used at the beginning of noun groups which refer to only one person or thing. The form an is used in front of words that begin with vowel sounds.
1 a WEAK STRONG or an WEAK STRONG
You use a or an when you are referring to someone or something for the first time or when people may not know which particular person or thing you are talking about.
A waiter entered with a tray bearing a glass and a bottle of whiskey.
He started eating an apple.
Today you've got a new teacher taking you.
I manage a hotel.
DET: DET sing-n
2 a WEAK STRONG or an WEAK STRONG
You use a or an when you are referring to any person or thing of a particular type and do not want to be specific.
...expensive make-up that we saw being advertised by a beautiful model...
I suggest you leave it to an expert.
Bring a sleeping bag.
...waiting for a bus.
DET: DET sing-n
3 a WEAK STRONG or an WEAK STRONG
You use a or an in front of an uncount noun when that noun follows an adjective, or when the noun is followed by words that describe it more fully.
The islanders exhibit a constant happiness with life.
He did have a real knowledge of the country.
Baseball movies have gained an appreciation that far outstrips those dealing with any other sport.
DET: DET n-uncount with supp
4 a WEAK STRONG or an WEAK STRONG
You use a or an in front of a mass noun when you want to refer to a single type or make of something.
Bollinger `RD' is a rare, highly prized wine.
DET: DET n-mass
5 a WEAK STRONG or an WEAK STRONG
You use a in quantifiers such as a lot, a little, and a bit.
I spend a lot on expensive jewelry and clothing.
I've come looking for a bit of advice.
DET: DET in quant
6 a WEAK STRONG or an WEAK STRONG
You use a or an to refer to someone or something as a typical member of a group, class, or type.
Some parents believe a boy must learn to stand up and fight like a man.
...the operation a patient has had.
DET: DET sing-n
7 a WEAK STRONG or an WEAK STRONG
You use a or an in front of the names of days, months, or festivals when you are referring to one particular instance of that day, month, or festival.
The interview took place on a Friday afternoon.
It was a Christmas when shoppers passed by expensive silks in favor of more practical gifts.
DET: DET sing-n
8 a WEAK STRONG or an WEAK STRONG
You use a or an when you are saying what someone is or what job they have.
I explained that I was an artist.
He was now a teacher and a respectable member of the community.
DET: DET sing-n
9 a WEAK STRONG or an WEAK STRONG
You use a or an in front of the names of people as a way of indicating that you do not know them or anything about them and you are saying their name for the first time.
The full address on a stick-on label was that of a Mrs P. R. Slater of Peterborough.
A Dr Matthew Owens was reported missing while on an expedition to north-eastern Turkey.
DET: DET n-proper
10 a WEAK STRONG or an WEAK STRONG
You use a or an in front of the names of people when you want to refer to someone else who has the same qualities or character as the person named.
When I listen to her play I can hear a new Nigel Kennedy.
DET: DET n-proper
11 a WEAK STRONG or an WEAK STRONG
You use a or an in front of a surname when you want to refer to someone who belongs to the family with that surname.
As far as I can recall, Patti was a Smith.
DET: DET n-proper
12 a WEAK STRONG or an WEAK STRONG
You use a or an in front of the names of artists to refer to one individual painting or sculpture created by them.
Most people have very little difficulty in seeing why a Van Gogh is a work of genius.
DET: DET n-proper
13 a WEAK STRONG or an WEAK STRONG
You use a or an instead of the number `one', especially with words of measurement such as `hundred', `hour', and `metre', and with fractions such as `half', `quarter', and `third'.
...more than a thousand acres of land.
...a quarter of an hour...
The skirts were shortened an inch or two.
DET: DET sing-n
14 a WEAK STRONG or an WEAK STRONG
You use a or an in expressions such as eight hours a day to express a rate or ratio.
Prices start at s13.95 a metre for printed cotton.
The helicopter can zip along at about 150 kilometres an hour.
DET: num DET sing-n
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