Yes it can. Some examples are:I like to do word puzzles.This is the word for word story told by the witness.We have to memorize this word list for homework.
No, "when" is an adverb. If it were an adjective, you would hear such things as "I really like that when car."
an adjective is a word that describes a noun (next time try to write ur ? corrwctly okay hunny)
No, it's a verb. To have, having, etc.
no it is a helping verb :)