This document discusses the proper usage of "during", "for", and "ago" when referring to periods of time. It provides examples of how to correctly use "during" to indicate when something happens within a period, and "for" to indicate how long something lasts. It also explains that "during" is preferred when referring to an entire period, while "in" can also be used but is less precise. Finally, it outlines that expressions using "ago" are normally used with past tenses, not present perfect, except when using "since" plus a time period ago.

1. During, for and ago
During and for
During is used to say when something happens; for is used to say how long it lasts.
Compare:
− My father was in hospital during the summer.
My father was in hospital for six weeks. (NOT ... during six weeks)
− It rained during the night for two or three hours.
I’ll call in and see you for a few minutes during the afternoon.
During and in
We use both during and in to say that something happens inside a particular period of
time.
We’ll be on holiday during/in August.
I woke up during/in the night.
We prefer during when we stress that we are talking about the whole of the period
The shop’s closed during the whole of August. (NOT ... in the whole of August.)
We often prefer during when we say that something happens between the beginning and
end of an event or activity (not a period of time).
He had some strange experiences during his military service.
(NOT … in his military service. )
I’ll try to phone you during the meeting. (NOT ... in the meeting.)
I met them during my stay in China.
Ago
position
expression of time + ago
I met her six weeks ago. (N0T ...ago six weeks.)
a long time ago
tenses
An expression with ago refers to a finished time, and is normally used with a past tense,
not a present perfect.
She phoned a few minutes ago. (NOT She has phoned...)
‘Where’s Mike?’ ‘He was working outside ten minutes ago.’
However, a present perfect tense is used with since... ago (as with since + any other time
expression).
We’ve been living here since about eight years ago.
I haven’t bought any since a week ago.