我以为他是男的，原来她是女的。

I had thought that he was a man, but it turned out that he was a woman.

Source: Tatoeba

Sentence Composition

1 我 wǒ
  1. I
  2. me
  3. my
2 以为 yǐwéi to think; to believe (often with the implication that the belief is mistaken – unless referring to one's own current belief)
3 他 tā
  1. (third-person singular) (since the early 20th century, usu. male) he; him; his
  2. (bound form) other; another; some other (as in 他日 tārì and 他人 tārén)
=4 是 shì
  1. to be (followed by substantives only)
  2. correct; right; true
  3. (respectful acknowledgement of a command) very well
  4. (adverb for emphatic assertion)
=4 是 shì variant of 是 shì
5 男的 nánde man
6 原来 yuánlái
  1. original; former
  2. originally; formerly; at first
  3. so, actually, as it turns out
7 她 tā she
=8 是 shì
  1. to be (followed by substantives only)
  2. correct; right; true
  3. (respectful acknowledgement of a command) very well
  4. (adverb for emphatic assertion)
=8 是 shì variant of 是 shì
9 女的 nǚde woman