The 5 for present participle: 1. I have TALKED to my parents about my exam 2. She has KNELT in front of the cross every time she has entered the church 3. He has FELT love for her since he met her 4. We have PRAYED for him since he became ill 5. They have SMOKED cigarettes since they started college
The 5 for past participle: 1. The money was STOLEN because the vault was open 2. I was HIT by a car last night when I was crossing the street 3. They left the food in the freezer and they forgot to take it out so after a few hours the food was FROZEN 4. In ancient cultures people were SACRIFICED in order to make gods happy 5. In the past, horses were RIDDEN by men only.
As you can see, passive sentences are the ones in which past participle is normally used. In a passive sentence you will say "horses were RIDDEN by men" instead of "men RODE horses", so you have to use verbs that can be used that way. For example, in the case of the verb "kneel", it would be difficult to use in past participle because a sentence in the passive form would make little or no sense at all.
