进厕所前先敲门。

Knock before entering the bathroom.

Source: Tatoeba

Sentence Composition

1 进 jìn
  1. to go forward
  2. to advance
  3. to go in
  4. to enter
  5. to put in
  6. to submit
  7. to take in
  8. to admit
  9. (math.) base of a number system
  10. classifier for sections in a building or residential compound
2 厕所 cèsuǒ toilet; lavatory

classifiers: 間, 處
3 前 qián
  1. front
  2. forward
  3. ahead
  4. first
  5. top (followed by a number)
  6. future
  7. ago
  8. before
  9. BC (e.g. 前293年)
  10. former
  11. formerly
=4 先 xiān
  1. beforehand; first; earlier
  2. at first; originally
  3. for the time being; for now
  4. (prefix) my late (in referring to deceased relatives older than oneself)
=4 先 xiǎn only used in 先馬／先马
5 敲门 qiāomén to knock on a door