Condition/Warning + 否则 + Consequence
The conjunction 否则 (fǒuzé) means 'otherwise' or 'if not' and is used to introduce the negative consequence that would follow if a condition is not met. It connects two clauses, where the first states a condition or warning and the second describes an undesirable outcome. It is more formal than 要不然.
你要早点出发,否则会迟到的。
nǐ yào zǎodiǎn chūfā, fǒuzé huì chídào de.
You should leave early; otherwise, you'll be late.
快把作业做完,否则明天交不了。
Kuài bǎ zuòyè zuò wán, fǒuzé míngtiān jiāo bù liǎo.
Hurry up and finish your homework, otherwise you won't be able to turn it in tomorrow.
我们必须节约用水,否则将来会没水喝。
Wǒmen bìxū jiéyuē yòng shuǐ, fǒuzé jiānglái huì méi shuǐ hē.
We must conserve water, otherwise there won't be any water to drink in the future.