She works a lot.
To find out what the subject of a sentence is, look at the verb first and then ask 'who (or what)?' In our sample sentence, the verb is 'works'. Add 'who (or what)' and you get: 'Who (or What)' works a lot? The answer is: She. 'She' is thus the subject of the sentence
What is the subject (in the nominative case) in these sentences?
My sister eats a Schnitzel. Meine Schwester isst ein Schnitzel.
The verb is 'eats'. 'Who (or what)' eats a Schnitzel? - 'My sister'.
'My sister' is the subject of the sentence, in the nominative case..
My sister plays (a game).
'Who or what' plays? My sister.
This computer is very expensive.
'Who or what' is very expensive? This computer.
Und jetzt auf Deutsch!
Meine Schwester isst ein Schnitzel.
'Wer oder was' isst ein Schnitzel? Meine Schwester.
Meine Schwester spielt.
'Wer oder was' spielt? Meine Schwester.
Der Computer ist sehr teuer.
'Wer oder was' ist sehr teuer? Der Computer.
The nominative case is also used for so-called predicate complements. Take a look at this sentence: John is a nice guy. You know now that John is the subject (in the nominative case) of this sentence: 'Who (or what') is a nice guy? John. Whenever you have a sentence in which the subject = something else (John = nice guy), the predicate complement (nice guy) is also in the nominative case because it is 'equal to' the subject. This commonly is the case when you have linking verbs like to be (sein) or to become (werd