Questions & Answers about Li portas bandaĝon kaj uzas lambastonon.
The -n ending marks the direct object in Esperanto. These are the things being acted on:
- Li portas bandaĝon = he wears/carries a bandage
- kaj uzas lambastonon = and uses a crutch
So bandaĝo becomes bandaĝon, and lambastono becomes lambastonon, because each noun is the object of a verb.
Li means he.
Si is a special reflexive pronoun, used when the object refers back to the subject, like himself / herself / itself in certain situations. But in this sentence, the subject is simply he, so Esperanto uses li.
- Li portas bandaĝon = He wears a bandage.
- Li lavas sin = He washes himself.
So si would not be used here as the subject pronoun.