I have seen that the use of "be + yet + to-infinitive" and "have + yet + to-infinitive" are often used interchangeably, e.g.:

[A] I am yet to contact him.

[B] I have yet to contact him.


  1. Are both of the structures grammatically correct ?
  2. What is the exact difference in meaning between these two structures?
  • I assume your first line was an intro; it was ungrammatical and rather confusing. I've removed it. I've also altered your 'to-infinitives' to bare infinitives where this makes things simpler, in line with modern treatments. Oct 11, 2017 at 10:33

1 Answer 1


This has been discussed over on ELL.

I think that the fixed expression have yet to (do something), meaning, as Collins says,

[to] have not yet (done something) we have yet to win

is potentially confusable with have to (do something), meaning 'need to do something'.

I have yet to treat a man with lupus.

which, though very formal, can mean that surgery isn't over for the day, even though 'I've never had to treat someone with lupus' is the more likely meaning. 'Yet', unlike 'still', can only be placed after and not before 'have'. Context will usually disambiguate between the modal 'still need to' and the non-modal 'as of now haven't' senses. 'I have yet to contact him' almost certainly implies that the speaker intends to try and that they haven't tried so far, as 'I haven't been able to reach him' would almost certainly be the choice for the other sense.


The expression be to do something has many senses. Relevant here are the 'moral obligation' sense

be to do something PHRASE FORMAL

1) used for telling someone what to do

[ie in the passive voice, indicating moral obligation] You are to stay here until I send for you.

but also the 'general arrangements' // 'preferred/intended course of action' senses (which I'd say overlap):

2) used for saying what has been arranged

The ceremony is to take place in the palace grounds.

3) used for saying or asking what should be done

What are we to do?

You are to be congratulated on your wise decision.


The bottom line is that both variants have different senses, which often overlap. Some individual examples will render the 'moral obligation / requirement / need' senses less likely or even inadmissible.

With 'I am yet to contact him', I'd say that the intended sense would normally be the non-modal 'I haven't contacted him to date', very similar to the 'have' variant. Using this for 'They still require/insist that I get contact him' would be a highfalutin' usage.

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