1.2 Aspects
The aspect of a verb does not indicate when an action takes place in time; it rather shows the relationship between the action and the passage of time as seen from the speaker's point of view.
There are two aspects in English: the continuous (also called the progressive) aspect expresses duration; the perfect aspect expresses completion. The combination of these two aspects makes the perfect continuous.
The continuous aspect
be + present participle (verb-ing)
The continuous aspect is expressed with the auxiliary be and the present participle -ing form of the verb. Depending on the time of the action, we use the past (was, were), present (am, are, is) or modal + infinitive (e.g. will be) form of be.
The continuous aspect focuses on the duration of an event. It expresses that the action was, is or will be in progress at a specific point in time or over a period of time. The point in time may be defined by a time expression (now, at 5 o'clock yesterday, this time tomorrow) or a clause (when I came home, when I come home). For the period of time, we can also use a time expression (all day yesterday) or a clause (while she was reading).
Examples of the continuous aspect:
Are you enjoying yourself? (now)
At 9 o'clock, I was sitting on the train.
When I came home, he was sleeping.
She must be waiting for me. (now)
Rob was hiking all day yesterday.
While she was reading, Bill was working on the computer.
In January, I'll be living at my brother's.
The perfect aspect
have + past participle
The perfect aspect is expressed with the auxiliary have and the past participle form of the verb. Depending on the time of the action, we use one of the following forms of have: the past (had), present (have, has), modal + infinitive (e.g. will have) or -ing (having).
The perfect aspect focuses on the completion of an event. It expresses that the action had, has or will have been completed by a specific point in time. This point in time may be defined by a time expression (by 5 o'clock) or a clause (by the time you get home, when I arrived).
Examples of the perfect aspect:
I've lived here for ten years. (from 10 years ago until now)
By 5 o'clock, he had finished the letter. (at some time before 5 o'clock)
When I arrived, they had already left. (at some time before I arrived)
Have you seen my new bike? (at any time up to now)
I will have done the ironing by the time you get home. (between now and when you get home)
He might have missed the train. (at some time before now)
Having taken the wrong turn, he ended up in a dangerous neighbourhood. (he turned before he found himself in a dangerous neighbourhood)
The perfect continuous aspect
have + been + verb-ing
The perfect continuous is not considered as an aspect in itself; it is rather a combination of the perfect and continuous aspects.
It is expressed with the auxiliaries have and been (the third form of be) and the (present participle) -ing form of the verb. Depending on the time of the action, we use one of the following forms of have: the past (had), present (have, has) or modal + infinitive (e.g. will have).
The perfect continuous expresses that the action had, has or will have been in progress for some time at a specific point in time. This point in time may be defined by a time expression (at 5 o'clock) or a clause (when she gets home).
Examples of the perfect continuous:
I've been waiting for this moment all my life. (from when I was born until now)
He's been ironing his shirts. (from some time in the past until now)
By 2005, George had been living in Scotland for 20 years. (from 1985 to 2005)
When Mary gets home, Kevin will have been sleeping for hours. (Kevin’s sleep lasting from some point in time before Mary gets home until she gets home)
I wouldn't have been sitting there if I hadn't had to. (from some time in the past until a later time in the past)