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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?

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That's really not a very good summary of the phenomenon. It's much easier to understand than that. Perhaps you'd better not read any further in OALD until you've gotten some basic concepts clearer. –  John Lawler May 2 '13 at 13:53
@JohnLawler thanks, what book can I read to understand the basic concepts clearer? –  Timothy Li May 2 '13 at 13:55
McCawley's The Syntactic Phenomena of English is much clearer, but it's a rather different approach; you can't just look stuff up -- you'll have to read the first part of the book (up to "Complements" which is where this phenomenon is treated). –  John Lawler May 2 '13 at 13:57
@JohnLawler I will. In my mind, I also treat those as complements, but it doesn't said this. –  Timothy Li May 2 '13 at 14:02

3 Answers 3

up vote 3 down vote accepted

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)]
  • 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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Why is Sheila not the direct object of persuade? The verb is "acting" on her. How is the infinitive clause being persuaded? –  Andrew Leach May 2 '13 at 14:51
The infinitive clause is not being persuaded. Sheila is being persuaded. The infinitive clause is what she is being persuaded of. Communicational bitransitive verbs like tell, persuade, convince, order, and explain all take two objects -- one identifying the receiver and the other describing the message. Also, "acting on" is not a useful test because it's vague and explains anything. The frame with bitransitive verbs is Source (su) -- Trajector (do) -> Goal (io). –  John Lawler May 2 '13 at 14:57
Many thanks,John. Though what you said(contains the materials you give) is new to me, I will learn these carefully because it's so interesting. –  Timothy Li May 2 '13 at 15:17
@JohnLawler That's what I thought. I (su) persuaded Sheila (do) to do something (io). But the answer says "to do something" is do. –  Andrew Leach May 2 '13 at 15:33
No, no. Sheila is IO (IO has to be animate to receive the communication) while the clause (the communication itself) is DO. –  John Lawler May 2 '13 at 15:42

A. Yes, you can think of those infinitives as objects; they serve a very similar function, even though infinitives are normally not so called.

B. "Why" is a difficult question. That's just the way it is. It is a special construction. You may want to read up on raising.

C. Persuade Sheila to chair is indeed similar, but still somewhat different. You can say I persuaded Sheila, and adding to chair the meeting doesn't change the meaning of the verb; however, in I'd love you to come, you can say I'd love you, but then love has a different meaning. That's the difference. The addition of the infinitive changes more than just the additional information. You could say the infinitive is more like a syntactical complement in the love sentence than in the persuade sentence.

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Now, since I can't think of to chair as the complement of Sheila, how should I think of the to chair in the sentence Can you persuade Sheila to chair the meeting? –  Timothy Li May 2 '13 at 14:32
Only transitive verbs can have direct objects, and bitransitive verbs can have indirect objects as well. Complement clauses can only be direct objects, but they usually interact with the indirect object if there is one. Persuade is bitransitive. This is what's called B-Equi in the trade; expect is only transitive, so the NP must be the subject of the infinitive; this is called B-Raising. See here for details. –  John Lawler May 2 '13 at 14:49
@JohnLawler: I was taught something like that (though in less technical terms), but the difference still doesn't seem all that significant on the whole. You could, for example, say that the predicate frame of expect changes to become very similar to that of persuade in the construction above; then it it could be said to have two complements. I know you will disagree, but it seems to me you need a complex theory while at first glance, and to some degree intuitively, the two constructions seem very much alike. Not saying that's wrong, but I'm still not entirely happy about it. –  Cerberus May 3 '13 at 3:47
@JohnLawler: ...I think you will need your for to differentiate between the two constructions. In Latin, you need the fact that the bitransitive verb can be passivised while leaving the infinitive intact, which is not possible with an a.c.i. But I suspect that this doesn't hold up very well in less-than-Ciceronian Latin. –  Cerberus May 3 '13 at 3:53
Whether for is deleted or not (normally it is), and whether to is deleted or not (normally it's not), and whether the subject NP is deleted or raised or neither, are all governed by the matrix predicate. All combinations (and many others) exist; indeed, when you look at the details, every verb has a different combination of obligatory, forbidden, and optional processes. –  John Lawler May 3 '13 at 3:58

1 I expect her to pass the driving test first time.

2 We'd love you to come and visit us.

3 Can you persuade Sheila to chair the meeting?

In 1 and 2 you can say

1a I expect something. And you can replace "something" by an object consisting of two parts, a noun + to-infinitive.

2a We'd love something. "something" can be replaced by: you to come and visit us.

In 3 this is not possible. You can't say: Can you persuade something. You would need two objects: Can you persuade Sheila into something. And here you can replace only "into something" by "to chair the meeting".

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