hé / tong / lǐ / yǒu / yī / tiáo / zhòng / yào / de / dàn / shū / bǎo / zhàng / le / xiāo / fèi / zhě / de / quán / yì

合同里有一条重要的但书，保障了消费者的权益。

The contract contains an important proviso that protects consumers' rights.