题目内容：

阅读下面材料，在空白处填入适当的内容（1 个单词）或括号内单词的正确形式。

While buying things online, many of us rely on customer reviews to understand the usage and 1.（perform）of a product. But many sellers are buying fake reviews to influence purchasing patterns. Review companies have 2.army of testers who post four - and five-star reviews on e-commerce platforms. More than 60,000 specialized testers throughout Europe write reviews quickly and 3.（rely）. Although Amazon 4.（fight） against fake reviews and has deleted some of them, the fake reviews won't stop 5. Amazon stops its practice of ranking products.