我不知道他是谁。

I don't know who he is.

Source: Tatoeba

Sentence Composition

1 我不知道 wǒbùzhīdào I don't know.
2 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)
=3 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)
=3 是 shì variant of 是 shì
4 谁 shéi
  1. who
  2. also pr. shuí