在緊急情況下，打電話報警。

In case of emergency, call the police.

Source: Tatoeba

Sentence Composition

1 在 zài
  1. to exist; to be alive
  2. (of sb or sth) to be (located) at
  3. (used before a verb to indicate an action in progress)
2 緊急 jǐnjí
  1. urgent
  2. emergency
3 情況 qíngkuàng circumstances; state of affairs; situation

classifiers: 個, 種
4 下 xià
  1. down
  2. downwards
  3. below
  4. lower
  5. later
  6. next (week etc)
  7. second (of two parts)
  8. to decline
  9. to go down
  10. to arrive at (a decision, conclusion etc)
  11. measure word to show the frequency of an action
5 打電話 dǎdiànhuà to make a telephone call
6 報警 bàojǐng
  1. to sound an alarm
  2. to report sth to the police