which (of three or more) / which one /

Nothing

what

(colloquial) current boyfriend

(slang) Alternative form of 彼氏 (kareshi, “boyfriend”)

everyone, one and all

気を付ける: to be careful, to watch out; to take care

to light a fire / to set on fire; to ignite; to set fire to / (figuratively) to spark; to ignite (excitement, debate, controversy, etc.)

Misspelling of きをつけて. Since o is written as を when used as a particle.

to find fault