I understand the meaning but not the sentence formation/syntax. In my mother tongue this would make no sense. I would rather say:

Who according to Tom saw him?

Perhaps the following will help to understand my problem

In normal question, we use this pattern: [question word] + auxiliary verb + subject + verb. For example:

  • Did Kate eat the cake? (Potential answer: yes/no)

  • Where did Kate eat the cake? (Potential answer: in the kitchen)

We also have questions that ask about the doer/agent of the activity. Pattern: question word + verb

  • Who ate the cake? (Potential answer: Kate)

In my sentence:

  • Who did Tom say saw him? (Potential answer: Kate)

The beginning of the question looks like a pattern for a normal question. However, we are asking about the doer/agent of the activity.

  • People don't ask "Who did Tom say" as a standalone question. It comes after the mention of who he saw. By itself, the question is confusing. In context, it comes together. Dec 14, 2023 at 18:56
  • 3
    @YosefBaskin I disagree - it's a perfectly natural question from my perspective. Who did Tom say {saw him / he saw / was responsible for the accident / he was buying a present for} ? It's a pretty common way to ask about who Tom said something about.
    – ColleenV
    Dec 14, 2023 at 19:47
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    What @ColleenV said. If prior context has clearly established that some unknown person is the current "topic", just "Who did Tom say?" is perfectly acceptable all on its own to ask who Tom suggested for the identity. But if the "unknown person" is specifically "someone who saw Tom*, and Tom himself has an opinion about who it might be, "Who did Tom say [it was that] saw him?" is fine. Dec 14, 2023 at 20:12
  • @ColleenV I would pedantically start two of your examples with Whom: Who did Tom say saw him? Whom did Tom say he saw? Who did Tom say was responsible for the accident? Whom did Tom say he was buying a present for? (Or, For whom did Tom say he was buying a present?)
    – shoover
    Dec 15, 2023 at 22:30
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    We're not directly asking about the doer/agent of the "saw him" activity, we're asking about what Tom said - we're basically inquiring about the name of the person that Tom mentioned. The "who" here is less "who saw him", and more "Hey, remind me again, who was the person that Tom referred to earlier?" And then the "saw him" part is just to offer more detail on what Tom was talking about. Dec 16, 2023 at 1:33

4 Answers 4


It is a bit difficult. I'll describe it in terms of Transformational Grammar: other grammars are available.

We start with

Who1 saw Tom2?

Then we embed that in a matrix "Tom said":

Tom2 said who1 saw him2.

Who is now doing heavy work: equivalent to something like the person1 was, who1.

Then this "fused relative", who is extracted from Tom said who saw him, leaving a trace:

Who1 did Tom2 say t1 saw him2.

  • Thanks for the answer. Could you explain it in a way that refers more to grammatical rules?
    – kyadere
    Dec 14, 2023 at 21:23
  • @Mari-LouA Imagine me asking the question 'How do you ask about the past in English?' My guess is that you wouldn't start by talking about 'matrix and fused relative'. You would explain by referring to grammatical rules. For example: Use one of the ways of talking about the past. Past Simple is the most universal one. Use did, then put the doer/agent of the action and then the verb in its basic form - e.g. Did he win? Take a look at what English learning books look like. The way it is explained is quite different from that in this answer.
    – kyadere
    Dec 14, 2023 at 23:30
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    Some learners have a more advanced knowledge of grammar and actually want a more profound analysis. Your command of English appears to be impressive, in fact the question you posed is more challenging for instance than a question comparing the simple present or the simple past.
    – Mari-Lou A
    Dec 15, 2023 at 0:12
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    @Mari-LouA Wow, I'll take the second sentence as a compliment. Nevertheless, I'm looking for an explanation that can be shown to learners rather than linguists.
    – kyadere
    Dec 15, 2023 at 0:18
  • @kyadere based on the analysis of this answer, you can extract the rule of WH-movement, I suppose. From the sentence "Tom said who saw him" it goes to relative phrase "Who [Tom said] saw him" to change the "who saw him" into subject, then change that into a question using simple past auxiliary "did" to get "Who did Tom say saw him", just like "I told them where to go" becomes "Where did I tell them to go" (this example uses bitransitive, easier to see the movement due to the object "them")
    – justhalf
    Dec 15, 2023 at 3:35

Let's try to come at it without using any grammatical language at all, to see if it's possible for clarity to emerge. Just as an experiment.

Did Tom say who saw him?

-- Yes. Tom did say who saw him.

Please tell me who saw Tom. Who did Tom say saw him?

NOTE: We are not asking, in that final question, merely about the identity of the person who saw Tom. We are asking who it was that Tom identified as the person who saw him.

Who did Tom say it was?

--It was Kate who saw Tom.



In English questions are usually formed by starting with a declarative sentence, replacing the unknown part with a questions word (who, what, where, how) and moving the question word to the front. So a sentence like

Tom hugged Bill.


Tom hugged whom?

which is a perfectly fine question. (It’s “whom” because Bill is the object of the verb.)

The problem is that you just can’t move whom to the front. If you did you would get

Whom Tom hugged? (*)

which is not a proper english sentence. I’m not sure why. (I’ll put a (*) next to phrases that aren’t something you should say.) But there is a work around. Instead of “Tom hugged Bill” you can say

Tom did hug Bill.

(Which is correct English, though not the usual way to say this.) Now we get

Tom did hug whom? (*)

(In contrast to “Tom hugged who?”, this is something no anglophone would say; it’s just a step on the path to the next one.) Now the “Whom” moves to the front and drags the did along with it.

Whom did Tom hug?

The auxiliary verb “did” moving to the front is important. An auxiliary verb moving to the front and leaving its The main verb behind really marks this as a question.


In your sentence it’s the same thing but more complicated because there are two verbs in the original sentence. Start with

Tom said that Bill saw him.

Simplify to

Tom said Bill saw him.

Replace Bill with who.

Tom said who saw him?

(I think it’s “who” not “whom” because Bill is the subject of saw and not the object of said, but I could be wrong.) It’s not very clear that this is a question, so we want to move “who” to the front. But again that leads to something an anglophone wouldn’t think is right. So, rephrase with “did”

Tom did say who saw him? (*)

Move the who to the front dragging the did with it.

Who did Tom say saw him?


The same idea works for present tense.

You eat what?


What do you eat?


Did Kate eat the cake?

is the same idea but without the question word. We start with the declarative sentence

Kate ate the cake.

There is no single part of this that we are uncertain about, but rather whether the whole event happened. So again add the did.

Kate did eat the cake.

Now the did moves to the front to make a question

Did Kate eat the cake?


Other auxiliary verbs can follow this pattern. E.g.

You have eaten.


Have you eaten?


Bob has met Chris?

could become

Has Bob met Chris?


Whom has Bob met?


Who has met Chris?


I'm going to provide more examples of this type of question:

What did Tom say battled him?

Where did Tom say he met him?

The concept of a "fused relative" Colin's answer mentions isn't as difficult as it sounds. You can consider these questions as if there are extra words implied here:

Who did Tom say [the person that] saw him [was]?

What did Tom say [the thing that] battled him [was]?

Where did Tom say [the place that] he met him [was]?

As TimR's answer demonstrates, the part "the __ that ___" is a relative clause, so it can be replaced by "it" in context.

The reason it's called a "fused relative" is that this relative clause is fused into the question word.

Fused relatives actually can be in sentences, too:

What he battled was a terrible cancer.

Where he went was previously uncharted.

The fused relative sentences can also be expanded into normal relative clauses:

The thing that he battled was a terrible cancer.

The place that he went was previously uncharted.

As before, you know these are normal relative clauses now because you can replace them with "it" as well:

It was a terrible cancer.

It was previously uncharted.

Hope this helps explain the concept!

  • "Who" isn't a fused relative here, it is an interrogative pronoun, since this is a question. Fused relatives with "who" are not common; see languagelog.ldc.upenn.edu/nll/?p=4665
    – sumelic
    Dec 16, 2023 at 0:53
  • @sumelic Does the answer still work despite the incorrect language or should I delete it entirely? Dec 16, 2023 at 12:16
  • Well, I think the answer works as an explanation of a fused relative so unfortunately, I'm not sure it's all that applicable here. It's correct that a fused relative can be rephrased to something like "the person that", "the thing that", "The place that". Distinguishing between fused relatives and interrogatives can be difficult; here is a question I found on that: Is 'who' here a relative word or an interrogative pronoun?
    – sumelic
    Dec 16, 2023 at 18:02
  • I'd hate to see the effort composing this answer go to waste so my suggestion I think would be an edit to clarify that the fused relative construction may not be involved in the original poster's sentence ("Who according to Tom saw him?").
    – sumelic
    Dec 16, 2023 at 18:03

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