彼女はドレスを縫っている。

she; her; her; girlfriend; sweetheart

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

dress

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to sew; to stitch; to weave one's way (e.g. through a crowd)