Learn English – What tense uses the future perfect “will have + past participle” and then adds a present participle

futurefuture-perfectnegative-raisingparticiplestenses

The sentence

I don't think the leaves will have started changing colors yet.

threw me for a loop today. I've been searching for hours, and I can't find anything close to a definitive answer on the question. At first glance it looks like it's simply Future Perfect. That can't be right, though, because the timing doesn't work out, being as how it's talking about an action in progress with the present participle. At the same time, I don't think it can be Future Perfect Continuous while it's missing the "to be" verb. I know that there is nothing grammatically wrong with the sentence, but for the life of me, I just can't define it.

Best Answer

I don't think (that) the leaves will have started changing colors yet.

Your question, I take it, refers to the subordinate clause

the leaves will not have started changing yet.

Not really belongs with this clause, but is moved to the head clause I think by 'negative raising'. I've moved it back because yet in the subordinate clause is ungrammatical without the negator.

The verb construction here, will have started, has the form of a 'future perfect', but it does not have future reference. Will here is employed as an epistemic modal: it expresses a necessary (or at least fairly confident) judgment or inference, just as it does when you hear a knock at the door and say "Oh, that will be Jack, I'm expecting him". You may call this verb construction a modal present perfect, and you may paraphrase the entire sentence thus:

I am not confident that the leaves have already started changing colors.

Changing colors is not part of this construction but a gerund-participle clause acting as complement of the verb start. Start takes a variety of complements:

  • a noun phrase: I have started my essay.
  • an infinitive clause: I have started to write my essay.
  • a gerund-participle clause: I have started writing my essay.
  • a free relative clause: I have started what someone else must finish. (But some grammarians would call this a noun phrase, too.)

It may also act as an intransitive verb with no complement: My essay has started.

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