Parts of speech

I'm reading up on English grammar, and I find it surprisingly difficult. I've been taught Dutch grammar in school, obviously, but in English class we only got very rudimentary grammar. Most we learned was by reading, listening and talking. So now that I'm faced with the exact definitions of participal phrases and adverb clauses, I find it a bit daunting.

Therefore, lest I forget:

verbals:
- like verbs in that they can have different tenses, can take subjects and objects and can be modified by adverbs
- unlike verbs in that they only describe action, not express it.
- 3 kinds: infinitive, gerund and participle

infinitive: (e.g. to write)
- used as a noun, adjective or adverb

gerund: (e.g. writing)
- used as a noun

participle:
- used as an adjective
- 3 kinds:
a) present participle (e.g. writing) show action going on
b) past participle (e.g. written) indicate action in the past
c) present perfect participle (e.g. having written) indicate past action extending into present time (This I remember from high school!)

Oh, and while we're on the subject of definitions:
adjective: describes or limits a noun or pronoun
adverb: describes a verb, an adjective or another adverb