Researchers report they have engineered an enzyme that can convert 90% of that same plastic back to its pristine starting materials.

Does that originate in spec TP and move to spec CP like in this sentence? enter image description here

  • Could you please share book title?
    – Tsutsu
    May 8, 2020 at 13:28
  • It's Analysing English Sentences second edition by Andrew Radford
    – user8104
    May 8, 2020 at 13:42
  • 1
    "That" is of course a subordinator, not a relative pronoun. Since the relativised element is subject of the relative clause, gap is located immediately after "that": "Researchers report they have engineered an enzyme [that ____ can convert 90% of that same plastic back to its pristine starting materials]"
    – BillJ
    May 8, 2020 at 18:39
  • 3
    For many English speakers that is a subordinator; but for many it is also a relative pronoun that can be the subject of a relative clause like this. English has no ISO standards for parsing, and if it did, we'd ignore them.
    – jlawler
    Oct 5, 2020 at 21:07

1 Answer 1


There is a difference between wh-relative clauses (1) and that-relative clauses (2). The first are formed by wh-movement, whilst the second are a result of a complementizer merged in the head of C:

(1) They said [CP that [TP they know [CP who [C ∅ [TP found the solution]]]]].
(2) They said [CP that [TP they know the key [CP [C that [solves the problem]]]]].

The wh-part in (141) (from Radford's book) is an adjunct. The wh-adjunct which is extracted from an A'-position will land in an A'-position (intermediate Spec,CP). This is how relative clauses such as (1) and (141) are formed.

However, (2) is formed by merging that in the head of C. There's no movement involved. Notice that in (1), the subject of the embedded verb find is who. who in this case is a subject-wh element. who may act as a subject and an object in other sentences. that cannot because it's a head. Head do not act subjects or objects.

Notice further that in (1), the wh-subject acts as a subject of the embedded TP who found the solution. In (2), the subject of this embedded clause (i.e., solves the problem) is the moved DP the key. Based on this, that in your sentence is a head not a specifier.

Researchers report [CP [TP they have engineered an enzyme [CP [C that [TP can convert 90% of that same plastic back to its pristine starting materials]]]]].

Do not take these labels for granted, the CP that can convert 90% etc. is an adjunct modifier of the NP enzyme. CP modifiers do no necessarily contain subjects.

  • If the relativised element is subject, there is no movement. The relative clause is not an adjunct, but a modifier in NP structure. Adjuncts are modifiers in clause structure.
    – BillJ
    May 8, 2020 at 18:58
  • The embedded clause is a matrix in, e.g., who do you trust most?, this is formed by wh-movement of who (an object in this case). The same rationale carries over to complex sentences, e.g., I know the man who you trust most. The theta structure of this sentence presupposes an object of trust. I trust X. X is who which was moved. This again carries over to subjects, I believe.
    – Tsutsu
    May 8, 2020 at 20:05
  • Thank you so much, but is it possible for spec TP to be unoccupied? Does it need some kind of PRO subject?
    – user8104
    May 9, 2020 at 0:21
  • PRO subject is required only in infinitival TPs, e.g., She wants [CP C[TP PRO to leave]]. In your sentence, we could put it this way: Researchers report [CP [C [PRO to have engineered an enzyme that can convert...etc.]]].
    – Tsutsu
    May 9, 2020 at 10:09
  • In "Who do you trust most?", "who" is a prenucleus linked to a 'gap' in object function. I think this analysis is better than invoking arcane theoretical concepts and formalisms.
    – BillJ
    May 10, 2020 at 13:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.