Omg is the abbreviation of oh my god, which means "My God" in Chinese. OMG expresses strong feelings and is often used to express the feeling of surprise.

Jk is the abbreviation of just kidding, which means joking in Chinese. Don't take it seriously

Lol is short for laugh out loud, which means: laugh loudly.

Maura laughed me to death, which means: laughing me to death.

This is an abbreviation that some foreigners prefer to use in daily chat.