Learn English – Feel confused about to-infinitive in a sentence

grammar

In order to understand the English grammar, I have to read the Grammar Section in OALD. I don't understand the grammar constituents of to-infinitives in these sentences. How can I understand them?

OALD said

  1. Eat and to eat are both the infinitive form of the verb. Eat is called a BARE INFINITIVE and to eat is called a TO-INFINITIVE. Most verbs that take an infinitive are used with the to-infinitive.

    • the goldfish need to be fed.
    • she never learned to read.

  2. Some verbs can be used with both a noun phrase and a to-infinitive. The noun can be the object of the main verb.

    • Can you persuade Sheila to chair the meeting?

    or the noun phrase and infinitive phrase together can be the object.

    • I expected her to pass the driving test first time.
    • We'd love you to come and visit us.

My question is that in 1, can I think of the to-infinitive (to be fed and to read) is the object of need and learn, respectively？ And in 2, why can her to pass or you to come be bound together to be the object of expect or love? At the same time, why I can't think of Sheila to chair in this way?

I love our language, but can't understand its grammar 🙁

Edit: What role is the to-infinitive playing in these sentences?

Best Answer

There are a number of different uses of infinitives;
one of them -- exemplified here -- is as a particular kind of Complement clause.

The answer to the first question is, Yes, the infinitive clauses can be considered the direct object of the verb (though not the infinitive -- that's just the verb in the clause; it's the clause that's acting like an object).

Incidentally, "to-infinitive" is not a useful term; most infinitives occur with to, and others don't, but they're all infinitives, and the presence or absence of to is determined by the context. To is not an intrinsic part of the infinitive, but is rather part of the ("For-To") Infinitive Complementizer. Requiring a special term for an infinitive with to is like requiring a special term for a woman wearing shoes; it's irrelevant, confusing, and unnecessary.

In the first cases, the sentence is parsed

  • She never learned [(for her) to read (something)]
    and
  • The goldfish need [(for the goldfish) to be fed (by someone)]
    -- which is derived via Passive from
  • The goldfish need [(for someone) to feed the goldfish]

The bracketed parts are the direct object complement clause, with all the parenthesized parts -- indefinites and predictable subjects -- dropped, leaving only the infinitive behind.

Once you get clear that any verb appearing in a sentence is the verb of a separate clause and that every clause has a subject and a predicate, things clear up. That's the key to understanding the next question.

In the second case, it's quite wrong for the OALD to describe them as "Noun plus Infinitive". There are two quite distinct types represented here, and they have very different syntax.

I persuaded Sheila to chair the meeting is parsed

  • I persuaded Sheila [(for Sheila) to chair the meeting]

whereas I expected her to pass the test is parsed

  • I expected [(for) her to pass the test]

In the first case, the verb persuade has an Indirect Object (Sheila), as well as a Direct Object infinitive clause. This object complement clause (for Sheila to chair the meeting) has a subject (for Sheila), which gets deleted because it's identical to the Indirect Object.

In the second case, however, there is only a Direct Object clause (for her to pass the test), and so the subject can't be deleted by identity. In that case, only the subject complementizer for is deleted, leaving her in subject position in the infinitive clause.

Which also happens to be object position in the main clause -- isn't English syntax fun? (I might add that there is a lot more detail and complexity here.

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