I came across the sentence (PEU, talking about future events)
We can use the future perfect to say that something will be completed
or achieved by a certain time.
Why did Swan use a here? I thought we never use a
with non-count nouns and since time is non-count we shoudn't use indefinite article before it. Couldn't you explain that?
Best Answer
time here is a count noun: meaning a moment in time or a point in time.
See ODO, definition 2.1, and the example sentences.
Another example:
I will have finished editing this post by an unknown time in the future.
I will have finished editing this post by some point in the future.
To make it more definite:
It is now 0510 UTC on 05 Dec 2014. I will have finished editing this post by 0515 UTC.
Before it gets to be 0515 UTC, I will have finished editing this post.
(Using will: I will finish editing this post by 0515 UTC.)
Time as a count nount can also mean an indefinite period of time (ODO 2.3).
Here is a famous English text that illustrates time as a count noun. In this case, time means indefinite period of time (see ODO for synonyms such as interval, stretch, season.) I include it, because of it shows over and over time preceded by the indefinite article. :)
Ecclesiastes 3 King James Version (KJV)
1 To every thing there is a season, and a time to every purpose under the heaven:
2 A time to be born, and a time to die; a time to plant, and a time to pluck up that which is planted;
3 A time to kill, and a time to heal; a time to break down, and a time to build up;
4 A time to weep, and a time to laugh; a time to mourn, and a time to dance;
5 A time to cast away stones, and a time to gather stones together; a time to embrace, and a time to refrain from embracing;
6 A time to get, and a time to lose; a time to keep, and a time to cast away;
7 A time to rend, and a time to sew; a time to keep silence, and a time to speak;
8 A time to love, and a time to hate; a time of war, and a time of peace.
And here is a popular song that uses these lyrics:
The Byrds - 'Turn, Turn, Turn' (on youtube)