正是

zhèngshì
is precisely

CEDICT

Entry Composition

1 正 zhèng
  1. straight
  2. upright
  3. proper
  4. main
  5. principal
  6. to correct
  7. to rectify
  8. exactly
  9. just (at that time)
  10. right (in that place)
  11. (math.) positive
=2 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)
=2 是 shì variant of 是 shì