Prepositions of Time and Duration
Prepositions of Time and Duration
1. to, From…..to, until
We use ‘to’ when we want to point to an exact time before the stated hour.
We use ‘from…..to’ to point to a period between the time when an activity or event begins (from) and when it ends (to).
When we use ‘until’, we are also dealing with the period of time but the focus is on when the activity or event ends.
Examples:
The annual general meeting ended at a quarter to six.
(The meeting ended at 5.45 p.m.)
The museum is open from 10 a.m. to 5 p.m.
(It is open for seven hours.)
They were playing football until dusk.
(The game ended at dusk.)
Remember:
Till and up to have the same meaning as until.
Till is more common in conversations.
Till and up to are use in conversation and in formal contexts.
Examples:
The baby kept me awake till 1 a.m.
Up to 1990, our school won the inter-school debating championship every year. In 1991, however, we lost to Jit Sin Secondary School.
Until can also be used with verbs in their negative forms to mean ‘not before the time stated’.
Example:
I didn’t finish mopping the house until 11 a.m.
(I did not finish mopping the house before 11 a.m. I only finished it at 11 a.m.)
2. at, between…and
We use at to point to exact times.
We use between…and to point out that an action takes place after a stated time and before the second stated time.
Examples:
Eric will arrive at your house at 4 o’clock this evening.
Sue will arrive at your house between 4 o’clock and 5 o’clock this evening.
(We do not know the exact time when Sue will arrive).
The company suffered losses between 1990 and 1992.
3. for, since
We use for to point to how long an activity, and event or situation continues or lasts (minutes, hours, days, months or years).
We use since with an event or time in the past to point out that the activity, event or situation is going on from that time to now.
Examples:
Lee stayed with her friend for a month before returning home.
John has been here since Friday.
4. We do not use the preposition of time in and on before noun groups that begin with the demonstrative adjective this.
Examples:
Mr. Wilson will be retiring this month. (right)
Mr. Wilson will be retiring in this month. (wrong)
I will see you this Friday. (right)
I will see you on this Friday. (wrong)
Remember:
The preposition at, in and on cannot be used before each, every, next, one and last.
Learning English by Uncle Teng 
marto said
this is useful
Rogerio said
How may I say?
The specimen was acclimated 24 hours.
The specimen was acclimated for 24 hours.
The specimen was acclimated by 24 hours.
Is there another form that would be the correct?