In English grammar, a subject is something that does something. An object is something that gets things done to it.
Jill went to the store.
Jill did something --she's the subject. The sentence is really about her. The verb ("went") describes what Jill did.
The store: Got something done to it (had Jill go to it). No verbs to describe anything about the store.
The store was smelly and made Jill sick.
In last sentence the store did something, and Jill was the thing done unto.
Actually, the store was musty which is what made Jill feel sick.
This time, the store and Jill are both subjects in the last sentence, but Jill is also an object.
More grammar explanations on subject and object, on Wiki.
Jill went to the store.
Jill did something --she's the subject. The sentence is really about her. The verb ("went") describes what Jill did.
The store: Got something done to it (had Jill go to it). No verbs to describe anything about the store.
The store was smelly and made Jill sick.
In last sentence the store did something, and Jill was the thing done unto.
Actually, the store was musty which is what made Jill feel sick.
This time, the store and Jill are both subjects in the last sentence, but Jill is also an object.
More grammar explanations on subject and object, on Wiki.