Using the indefinite article to express rates

The indefinite article is used between two noun groups to express a rate or ratio. You can talk about prices, salaries, and speeds in this way.

as fast as 500 kilometres an hour.

rising by 1 per cent a year

a thousand pounds a week.

She worked 14 hours a day.

This construction can also express the frequency with which something happens, using 'once', 'twice', 'three times', and so on.

Kate visited him daily, sometimes twice a day.

You can express a similar idea more emphatically with 'each' or' every'. In more formal or technical contexts, 'per' is often used.

Approximately 10 per cent of families move each year.

...twenty or thirty times every second.

At the end of 1973 membership fees were raised to 25p per month per head (three pounds per year).

Note that it is also possible to use the in rates denoting prices, but this is very rare.

Petrol costs around three pounds the gallon.

Using the indefinite article with abstract uncount nouns

Many abstract uncount nouns, that is, nouns referring to things which cannot be seen, touched or measured, can be used with the indefinite article when an adjective is used with them. For example, if you talk about 'a sudden violent hatred', you mean a particular kind of hatred which is sudden and violent.

a passionate hatred of feminists.

working up a passing anger

a certain quaint charm.

Compare this with their use as uncount nouns when there are no adjectives.

How long can hatred last?

...in a voice choked with anger.

He had neither charm nor humour.

You don't have to use the indefinite article with such nouns just because of the adjectives; you can still use them without an article if you don't want to emphasize their individual, particular nature.

...a man of immense personal charm.

Instead of adjectives before the noun, you can have some description after it, for example a clause beginning with 'that'

....a charm that contains heavy doses of boyishness.

CHAPTER 4: SPECIFIC USES OF THE DEFINITE ARTICLE