zhè / bǐ / kuǎn / zi / shì / nǐ / shàng / ge / yuè / jiè / gěi / wǒ / de / wǒ / jīn / tiān / yí / dìng / huán / nǐ

这笔款子是你上个月借给我的，我今天一定还你。

This sum of money is what you lent me last month, and I will definitely repay you today.