。
She sat down and smoked a cigarette.
Literal
She [topic-は] sit [then-て] cigarette [object-を] smoked.
The te-form 座って sequences 'sat down' before 'smoked a cigarette,' chaining two actions into one breath without requiring an explicit 'and.' タバコを吸う is the standard collocation for smoking — 吸う ('to suck, inhale') is reused for any inhalation: タバコを吸う (smoke), 空気を吸う (breathe in air), ストローで吸う (suck through a straw). 煙草 is the kanji form (often written in katakana タバコ for casual writing) — both are pronounced タバコ, originally a Portuguese loanword (tabaco) so deeply naturalized that the kanji feel more native than borrowed.