如果就

rú guǒ yǒu rén lái diàn huà jiù shuō wǒ bù zài jiā

如果有人来电话，就说我不在家。

If anyone calls, tell them I'm not at home.

rú guǒ yù huǒ zāi jiù lì jí àn jǐng líng

如果遇火灾，就立即按警铃。

In case of a fire, ring the alarm bell.