it is what powers the giant advertising and marketing industries in their relentless attempts to map and exploit our cognitive and emotional vulnerabilities.
请问what在从句中作什么成分?能详细讲一下what在从句中的用法吗?
as per sth(following sth that has been decided)中的as应该是介词吧。还有as per usual,这里的as词性。The work was carried out as per instruction.It also require grain purchasers to conduct quality checks as per national rules.