下下

zuì hǎo bù yào shǐ yòng xià xià de hù fū pǐn

最好不要使用下下的护肤品。

You'd better not use the most inferior skin care products.

xià xià gè yuè

下下个月

the month after next

xià xià xīng qī

下下星期

the week after next

nǐ hái jì de xià xià zhōu shì sū qiàn de shēng rì ma

你还记得下下周是苏茜的生日吗？

Have you remembered it's Susie's birthday the week after next?