萬一發生火災，按鈴。

In case of fire, ring the bell.

Source: Tatoeba

Sentence Composition

1 萬一 wànyī
  1. just in case
  2. if by any chance
  3. contingency
2 發生 fāshēng to happen; to occur; to take place; to break out
3 火災 huǒzāi serious fire (in a city or a forest etc)
4 按鈴 ànlíng to ring (to produce the sound of a bell or a similar sound)