past participle - verbal form ending in -d or -ed used as an adjective  

• irregular verbals don't need -d or -ed endings
• modifies noun or pronoun
• comma separates past participial phrase from sentence if it's at the beginning or is nonessential to the meaning of the sentence
• don't use a comma if the past participial phrase is essential
• ex. loved, jumped, thrown
• ex. well-loved teacher, jumped by thieves, thrown by catcher

infinitives - "to + verb"; has 5 functions; only use commas if it starts the sentence  

• 1. adverb - Those people came to be photographed.
• 2. adjective - She has a goal to lose ten months.
• 3. subject - To mimic people is the ultimate form of flattery.
• 4. predicate nominative - My plans are to take over the world.
• 5. direct object - Do you love to read these notes?