當他進來的時候, 我正在寫信。

I was writing a letter when he came.

Source: Tatoeba

Sentence Composition

=1 當 dāng
  1. to be
  2. to act as
  3. manage
  4. withstand
  5. when
  6. during
  7. ought
  8. should
  9. match equally
  10. equal
  11. same
  12. obstruct
  13. just at (a time or place)
  14. on the spot
  15. right
  16. just at
=1 當 dàng
  1. at or in the very same...
  2. suitable
  3. adequate
  4. fitting
  5. proper
  6. to replace
  7. to regard as
  8. to think
  9. to pawn
  10. (coll.) to fail (a student)
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 進來 jìnlái to come in
=4 的 de
  1. of; ~'s (possessive particle)
  2. (used after an attribute when it modifies a noun)
  3. (used at the end of a declarative sentence for emphasis)
  4. (used after a noun, verb or adjective to form a nominal expression, as in 皮革的 pígéde "one made of leather" or 跑堂兒的 pǎotángrde "a waiter (literally, one who runs back and forth in a restaurant)" or 新的 xīnde "new one")
  5. also pr. dì or di in poetry and songs
=4 的 dī a taxi; a cab (abbr. for 的士 dīshì)
=4 的 dí really and truly
=4 的 dì (bound form) bull's-eye; target
5 時候 shíhou
  1. time
  2. length of time
  3. moment
  4. period
6 我 wǒ
  1. I
  2. me
  3. my
7 正在 zhèngzài to be in the process of (doing sth); to be currently ...-ing
8 寫信 xiěxìn to write a letter