不然 / 要不然 / 否则【bùrán / yàobùrán / fǒuzé】

不然 starts the second half of a sentence and says what will happen if the first half doesn't. The first half is usually advice, an order or a plan.

The second half often has 会 or 要 for the consequence, or 就 to link it tightly.

Where it goes

不然 goes at the very start of its clause, before the subject.

• × 你快点儿，我们不然会迟到 → 你快点儿，不然我们会迟到

要不然, 不然的话 and 否则

要不然 and 不然的话 mean the same as 不然 and are just as spoken. 否则 is the written form, for notices, instructions and essays.

At the start of a reply, 要不然 also offers another choice: "or else, how about …".

Looking back

不然 also works for the past: the first half is what happened, and the second is what would have happened instead.