Questions & Answers about Jeg kæmper med kufferten.
Because jeg is the subject form of I.
- Jeg = I
- Mig = me
In Jeg kæmper med kufferten, the speaker is the one doing the action, so Danish uses jeg.
Compare:
- Jeg kæmper = I struggle
- Hun hjælper mig = She helps me
Kæmpe is the infinitive form, meaning to struggle or to fight.
In a normal present-tense sentence, Danish usually adds -r to the infinitive:
- at kæmpe = to struggle
- jeg kæmper = I struggle / I am struggling
So kæmper is the present tense form.