當你值勤時最好不要抽煙。

You had better not smoke while on duty.

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 你 nǐ you (informal, as opposed to courteous 您 nín)
=2 你 nǐ you (Note: In Taiwan, 妳 is used to address females, but in mainland China, it is not commonly used. Instead, 你 is used to address both males and females.)
3 值勤 zhíqín variant of 执勤 zhíqín
=4 時 Shí surname Shi
=4 時 shí
  1. o'clock
  2. time
  3. when
  4. hour
  5. season
  6. period
5 最好 zuìhǎo
  1. best
  2. had better ...; it would be best to ...
6 不要 bùyào don't!; must not
7 抽煙 chōuyān variant of 抽烟 chōuyān