以为 (mistakenly think)
"I thought… (but I was wrong)"
- to think (i.e. to take it…以为 = "to think / assume" — and usually you turned out wrong.
- I / me我to think (i.e. to take it…以为today今天to be / is是Sunday星期天 = "I thought today was Sunday (it's not)."
- Unlike to think / believe认为, to think (i.e. to take it…以为 hints at a mistaken belief.
Subj + to think (i.e. to take it…以为 + Clause
- to think (i.e. to take it…以为 reports a belief that reality then contradicts.
I我thought以为you你leave走了。
- I / me我to think (i.e. to take it…以为you你to walk走(completed / change)了 = "I thought you'd left (but you hadn't)."
Practice
I thought you'd left (but you hadn't): 我 ____ 你走了。
以为 + Clause = (mistakenly) thought: 我以为你走了.
Practice
以为 usually implies the speaker turned out to be right.
Opposite — 以为 hints the belief was WRONG.
to think (i.e. to take it…以为 vs to think / believe认为
- to think (i.e. to take it…以为 = a (mistaken) assumption; to think / believe认为 = a considered opinion.
Explore
Correct or broken?
以为 admits a mistaken belief — what you THOUGHT, before reality corrected you.
Practice
How does 以为 differ from 认为?
以为 = mistaken assumption; 认为 = a considered opinion.
Recap
Key idea
- to think (i.e. to take it…以为 + Clause — "(mistakenly) thought / assumed"
- I / me我to think (i.e. to take it…以为today今天to be / is是Sunday星期天 (I was wrong)
- to think (i.e. to take it…以为 = mistaken; to think / believe认为 = a held opinion
Read the full reference: HSK 4 grammar — Verbs.