'TO' initiating a phrase as a preposition

[CarlosFelipe]

TO determine whether a change is simplification, incremental, or re-architecting, the following activities are undertaken:...

I suppose that 'TO' plays the role of a preposition in this phrase.

In this case, how can I make sure that 'TO' is really a preposition (like 'In order to determine...') or it is only a use of the infinitive 'TO DETERMINE'?

I have learned that all verbs needs to have ING after prepositions.

If 'TO' is playing the role of a preposition, shouldn't the word 'DETERMINE' have 'ING' in the end?

Thanks!

Felipe

[Tukanja]

You have to learn grammar from grammar books.
I need to go to my mountain place to repair my new toy; an IHC (GB) made crawler loader.
The loader isn't in so good condition that I am to spend both a lot of time and money repairing it.

All the blue coloured words are the infinitive forms of the main verbs in the phrases.
The word "to" is used to form, so called full infinitive, actually, the Infinitive.
In some cases the word "to" can represent not itself only but the main verb as well. That's the case when the main verb is mentioned in the previous sentence.
Sometimes, in some cases, we rather use the bare Infinitive form instead of the Infinitive.

The red coloured word is the Present participle.

Sometimes we put the preposition "to" before the Gerund form of a verb which, for example, represents something we expect to happen in the future as in the phrase

I look forward to hearing from you.

[Joe]

Tukanja has given you a great answer.

Just remember that prepositions come before NOUNS (or words like nouns such as noun phrases, pronouns etc). A preposition cannot come before a verb. We can convert verbs to nouns (or strictly gerunds) by adding -ing. (Don't confuse this with the present participle as in: They are running.) It is all explained more fully at:

Prepositions Rule

Try the quiz question on the above page to check that you really understand

[CarlosFelipe]

Thank you all for the explanation.

Please, have a look:

http://www.englishclub.com/esl-forums/v ... 99&t=64059

The explanation above confused me a little bit.