There are two basic kinds of verbs: Active Verbs and Stative Verbs. With active verbs, the subject does something to the object, like this,
Active: The car hit me! (Subject)
Passive: I was hit by the car. (Subject)
With stative verbs (e.g., BE, seem, feel) the subject does nothing,
She is a teacher.
He seems happy.
I feel sad.
In fact, the subject of a stative verb is either renamed or described by the word that follows the verb,
She is a teacher -> She = a teacher ('She' is renamed as 'a teacher')
He seems happy -> He = happy ('He' is described as 'happy')
I feel sad -> I = sad. ('I' and described as 'sad')
With stative verbs, the subject does not act upon the object. (Please note, technically stative verbs do not have objects. That is, they have what's called, a subject complement. The word that follows a stative verb (i.e., a teacher, happy, sad) is called a subject complement.
Given sentence 1.,
1. The leaves fell to the ground. (Subject)
notice the subject 'The leaves' doesn't do anything to 'to the ground'. 'to the ground' is the location where the leaves fell. It's an adverb phrase. :wink: If you ask the question "Where?" and the response you get is a location like 'to the ground', then you know you're dealing with an adverb. In short, the verb 'fell' is not active, and the reason it's not possible to place it in passive voice.
1a. The leaves were felled. (Ungrammatical)
Given sentence 2.,
2. I usually agree with my sister. (Subject)
the subject does not do anything to the object 'my sister'. Note that, 'agree with' is a phrasal verb.
2a. My sister was agreed with (by me). (Ungrammatical)
In this case, the meaning of the verb 'agreed with' requires at least two primary people (i.e., X agrees with Y), but in the passive voice one is reduced to secondary importance by being placed at the end of the sentence attached to a by-phrase (i.e., by me).
Note that, it's possible to passivize 'agree' if its object is not a person, like,
2b. Active: We agreed to it. (Object)
2c. Passive: It was agreed (to). (OK)
With 'agree', when people are involved, it's best to use active voice. :wink:
Given sentence 3.,
3. John came to our house. (Subject)
the subject doesn't do anything to 'to our house'. 'to our house' describes where John came. It's an an adverb. :wink:
Q: Where did John come?
A: To our house. (Adverb)
-ing expresses an act (i.e., acts upon, a doer)
-ed tells us more about the noun by describing the noun
If someone steals a car, it is a stolen car. :D
a. a stolen car -> the car is stolen (describes).
b. stealing car means, the car steals things. (doer)
Note that, the car acts upon things.
If you plan an event, it is called a planned event. :D
a. planned event means, the event is planned. (describes)
If a committee plans something, it is called a planning committee. :D
a. the committe plans/acts. (doer)
If the weather freezes things, it is called freezing weather. :D
a. the weather acts. (doer)
If you break your pencil, you have a broken pencil. :D
a. broken describes the pencil.
b. breaking means, the pencil acts upon things and breaks them.
'broken' is the past participle of 'break'. :wink:
All the best, :D