The 'wonderful' world of the perfect tenses:
Future perfect and future perfect continuous
Is there an easy answer to what exactly are the perfect tenses in English?
Written by Roger Hartopp, adapted from his book Typical Errors in English, and from Advanced Grammar in Use by Martin Hewings
This is a tense used to describe an act that is expected or predicted to be completed, ended, achieved, or done and dusted by a particular point in the future, but does not state exactly when.
For example, you’re flying to Beijing on Monday, and this is the starting point of your ‘story’. Any acts you mention as completed before that point (but after making your statement that you will be flying to Beijing on Monday) go into the future perfect:
By next Monday (the day you are flying), I’ll have changed my money, (I’ll have) packed my bags, (I’ll have) bought all my travel guides and (I’ll have) begun my holiday! We use will + have + past participle.
The future perfect can also be used to say what we believe is happening around now:
Most Apple users will have bought the new iPhone by now.
Hopefully it should be at this time that Julie will have arrived for her job interview.
It's always around now that they'll have cooked breakfast.
With the future perfect, we usually mention the future time, particularly if it is a time that we expect, or predict to complete something:
I'll have prepared everything needed to move out of the house by the weekend.
Next Monday we'll have completed the house painting.
By this time next Wednesday I'll have finished all my exams!
The future perfect passive is will have + been + past participle:
The room will have been cleaned when the guests arrive. (but we don’t know who will clean it, or who will do it is not important)
By this time next week the house will have been demolished.
I'm sure the wedding party will have been organised properly when it comes to the big day itself.
Future perfect continuous
Now I don't remember who it was, but this particular teacher described this particular tense as being almost useless to the point that, as learners, you don't really need to know about it. Well, for sure I rarely use it, if at all, in conversation, but in certain situations it does become necessary.
Anyway, what is it? Well, it's a tense used to describe a continuous activity that will still be (or is predicted to be) happening by a particular point in the future, usually after a decision or arrangement made in the past.
For example, you’re working on a difficult project. You started work on the project five months ago and expect to be still doing the project when the following month begins: By next month, I’ll have been working on this project for half a year. We use will + have + been + –ing.
We can also use the future perfect continuous to state when a continuous activity is expected or predicted to be ended, completed or achieved by a particular point in the future:
I realised only the other day that I’ll have been living in Poland for 23 years by next April – in my mind that will be some achievement!
The ceasefire in the African state of Murumba will officially start at midnight on Monday, when at this point the two sides will have been fighting for just over five years.
The future perfect continuous can be used to say what we think was happening at a point in the past:
I’m sure Julie will have been asking herself why she spent so much money on a new pair of shoes after they fell apart in the church at Jane and Dave’s wedding!
Fred will have been really kicking himself for not playing the lottery last week - his numbers came up!
As with the future perfect, we can also use the future perfect continuous to say what we believe or imagine is happening now:
Apple users will have been queueing all day and all night to be the first to get the new iPhone.
Many people will have been worrying for some time about the effects of COVID-19.
It is also used when mentioning the future time, particularly when we are only focussing on the continuous activity:
By the weekend I'll have been living in this house for over 60 years!
On Monday I'll have been studying economics continuously for five years.
Next Friday I’ll have been working on these English exercises for six days!
Perfect continuous passive, past continuous passive and future continuous passive
As a general rule, we don’t really use the perfect continuous tenses in the passive although they do exist. They are clumsy and I’ve probably never, ever spoken them or even written them! Until now!
The project had been being worked on for some time (past perfect continuous – urgh!);
The project has been being worked on (present perfect continuous – argh!);
The project will have been being worked on by the team for ten years. (Future - NO!)
I’m going to be prescriptive here. Please. I don’t care what the grammar pedants say, but just don’t use the perfect continuous tenses in the passive. They’re just awful, okay?