0 abbreviation for instant messaging -- 簡訊,即時消息(instant messaging的縮寫)
1 abbreviation for intramuscular -- 肌內的(intramuscular的縮寫)
2 short form of I am -- (I am的縮略形式)
I'm so happy for you! 我真替你高興!
I'm determined to get a better job.
I've told Steve I'm not interested, but he keeps asking me out.