This form of the verb is frequently the principal word of a phrase used as a subject or as an object, complement; as, To read good books is profitable; I like to read good books. Here also the form with to is equivalent to the participle form reading. Reading good books is profitable.
As this form of the verb names the action in an indefinite way, without limiting it to a subject, we call it the +Infinitive+ (Lat. infinitus, without limit). For definition, see Lesson 131. The infinitive, like the participle, may have what is called an assumed subject. The assumed subject denotes that to which the action or being expressed by the participle or the infinitive belongs.
Frequently the infinitive phrase expresses purpose, as in the first example given above, and in such cases to expresses relation, and performs its full function as a preposition; but, when the infinitive phrase is used as subject or as object complement, the to expresses no relation. It serves only to introduce the phrase, and in no way affects the meaning of the verb.
The infinitive, like other forms of the verb, may be followed by the different complements.
Analysis and Parsing.
The +infinitive phrase+ may be used as an +adjective modifier+ or an +adverb modifier+.
1. The hot-house is a trap to catch sunbeams.
hot-house | is \ trap
============|================
\The | \a \to
\ catch | sunbeams
\———-'—————
+Oral Analysis+.—To introduces the phrase; catch is the principal word, and sunbeams completes it.
+Parsing+.—To is a preposition, introducing the phrase and showing the relation, in sense, of the principal word to trap; catch is a form of the verb called infinitive; like a noun, it follows the preposition to and names the action, and, like a verb, it is completed by sunbeams.