To as preposition or as part of infinitive

Q:

When is "to" a preposition?

In the following phrases "to be accustomed to"; "to be used to" and "to object to" is the "to" a preposition and that´s why the verb that follows the "to" is in the gerund?

Are there other "to" forms followed by ing?

Is "to" a preposition when it´s followed by a noun/noun phrase?

In sentences such as

a) Some investors are tempted ____ (sacrifice) savings.

b) Of these, about 10,000 were advised ____ (continue) _____ (take)antibiotics....

What is the correct form of the verb in parentheses? Is there more than one possible answer?

If there's a possible inclusion of a "to" + verb, would the "to" be the infinitive, not a preposition?

vera
vcqm@ruralsp.com.br
Posted 20 February 2003

"To" is a preposition in the phrases you mentioned, and so would be followed by a noun, a pronoun, a gerund, or a gerund phrase, as in these examples:

(1)	If you live in Alaska, you'll soon get accustomed to cold weather.
(2)	I'll never get used to living in cold weather. I've always lived in the tropics.
(3)	I object to their principles. Actually, I object to their not having any principles at all.

In correctly formed English sentences, when "to" is followed by a noun, a pronoun, a gerund, or a gerund phrase, the "to" is a preposition. There are many expressions, including some with past participles, in which "to" is a preposition. Here are a few in example sentences:

(4)	I look forward to hearing from you soon.
(5)	They're committed to making a success of the venture.
(6)	The organization is dedicated to improving the lives of poor children all over the world.

Besides appearing as a preposition, as in the sentences above, "to" is often part of an infinitive or infinitive phrase, as in your sentences (a) and (b). Your sentence (a) is correct, with the verb following "tempt" in the infinitive form. A verb following "tempt," active or passive, is in the infinitive form:

(a)	Some investors are tempted to sacrifice savings.

And your sentence (b) is also correct using an infinitive:

(b)	Of these, 10,000 were advised to continue?/b>

When "advise" appears in the passive, it takes an infinitive, as in your sentence (b).

When "advise" appears in the active voice, under some circumstances it is followed by a gerund, and under other circumstances it is followed by an infinitive. For example, when "advise" doesn't have an object and is followed immediately by a gerund:

(7)	Some doctors advise taking vitamins to ensure good nutrition.

On the other hand, when "advise" has an object, when it is followed by a noun or a pronoun and then by a verb, the verb is in the infinitive form:

(8)	My doctor advised me to take Vitamin E for my skin condition.

Students need to learn which verbs follow gerunds (We enjoyed watching the Olympic Games on TV), which follow infinitives (Now we can afford to buy a new house!), which follow either with little or no change in meaning (They began dancing / to dance), and which follow either with a different meaning (Please stop talking / to talk).