For example,
1) My shoes wore out. My shoes have been worn out.
Are they both correct? If so, what is the difference and which one is more common?
2) My patience began to wear out. My patience began to be worn out.
Are they both correct? If so, what is the difference and which one is more common?
When a verb has no object, we call it intransitive:
Shoes wear out.
When a verb takes an object, we call it transitive:
Running on concrete wore out his knees.
"His knees" is the object. "Running on concrete" is the subject.
We can "flip" a transitive verb in the active voice (see the sentence about "knees" above) and make it a passive construction:
His knees were worn out by running on concrete.
We can omit the agent (that which performs the action):
His knees were worn out.
Something wore his knees out, but we don't know what it was. Was he a fireman who climbed ladders all day? In this form, we're basically saying his knees are in certain state or condition, since the agent is unexpressed.
