it depends on what what the sentence is about but somethimes yes
It.
The verb in the sentence is: changed
He continued to dilate on the subject for what seems forever. or Darkness and light will cause your eyes to dilate.
this sentence is going to be continueing forever until i decide to end it.
I will keep my favorite toy forever
The subject of the sentence is "you"
A subject in a sentence is who, what, or where the sentence is about.
No it is not a sentence. You might try: I will cherish you forever.
The subject is who or what the sentence is about.
You is the subject of that sentence.
This essay is going to take forever.He spends forever in the bathroom.I will love you forever and ever.
This event is the subject changedverb Alaska is the object (place) forever)time)