Pǎo jìn jiàoshì de shíhòu, tā yǐjīng shì gè luòtāngjī le.
By the time she ran into the classroom, she was already drenched.
Tips
memory
落 (to fall into) + 汤 (soup/hot water) + 鸡 (chicken) — a chicken that fell into a pot of soup. Picture a bedraggled wet chicken and you'll never forget this one.
usage
落汤鸡 is a vivid colloquial metaphor for a person who is completely soaked by rain or water. It can also convey a sense of embarrassment or pathetic condition.