Gerunds: complement and object of a sentence. [How to differentiate them?]

Tenacious Learner

Senior Member
Hi teachers,
I know that we can use a gerund as the subject, the complement, or the object of a sentence, but in the following two sentences, how can I differentiate if it's the complement or the object of the sentence? Both gerunds have a verb in front of them (is, enjoy). Is it because a gerund must be the complement of the verb "be" if there's a noun or a noun phrase after it?

1. Her favourite hobby is reading. (Complement of the sentence)
2. I enjoy reading (Object of the sentence or object or complement of the verb)

Noun phrase:
The hardest thing about learning English is understanding the gerund. (Complement of the sentence)

Thanks in advance.
Last edited:
  • entangledbank

    Senior Member
    English - South-East England
    After a bit of thought, I think there is a clear test. An object can be fronted for emphasis:

    I enjoy well-written novels.
    Well-written novels I enjoy.
    I enjoy reading history.
    :tick:Reading history I enjoy.

    But catenative complements of any kind can't be:

    The postman is knocking at the door.
    :cross:Knocking at the door is the postman.
    Mary continued reading her novel.
    :cross:Reading her novel Mary continued
    Mary considered writing a novel.
    :cross:Writing a novel Mary considered.

    Your first example is different, because equations can be reversed:

    Theresa May is the prime minister. The prime minister is Theresa May.
    Her favourite hobby is reading. Reading is her favourite hobby.


    Senior Member
    English - South-East England
    That doesn't show that anything moved. That shows that an equation between A and B can be expressed as either 'A is B' or 'B is A'. It doesn't show that we all start by creating an internal sentence 'A is B', then mentally move B to the front, then mentally move the verb as a consequence, then speak the resulting sentence 'B is A'. This is actually an issue in scientific theories of syntax: do elements of sentences get thought of in the place where they're spoken, or do internal rearrangements happen, and if so, what? I have no strong opinion on it, but linguists now generally prefer to avoid explanations with a lot of movement.
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