inifintive and gerund

[unicorn]

For Gerund and Infinitives, does a main verb always precede them? But I have found some examples that are also infinitive, for example: To smash a spider.

How can I tell what is bare infinitive? I have read that if some modal verbs precede the infinitive then, it’s a bare infinitive, is that correct?
I have also read that infinitives can be a verb, adjective and adverb is that true?

[schetin]

Hi Unicorn,

For Gerund and Infinitives, does a main verb always precede them?

Gerund is a verbal, having mainly the functions of Noun. It is never preceded by a 'main verb'.
Infinitive (or 'the name of a purpose') is different in that it can have various functions:

Subject - To master a language is not so easy as it may seem.
Attribute - This will be the night to remember.
Object - I'd like you to answer my questions.
Adverbial of purpose - You have to know 80% of the answer (in order) to pose a question correctly.

Some forms coincide with the Infinitive form, when the latter is used without particle 'to' (as with modals). The easiest way to check whether Infinitive is used is to use it with negation.
Say, Imperative is such a form:

Stand up; Open the books; &c.

The negative form of Infinitive will be:

not to stand up; not to open the books; &c.,

while Imperative form will be:

Don't stand up; don't open the books; &c.

If it helps,
Slava