请问 what is known as 引导的是什么从句啊?

what is known as the middle income trap given its still rapidly growing productivity整句话做avoid的宾语从句 再问： 为什么用what？what在宾语从句中作主语吗？ 再答： 对, what在宾语从句中做了主语，所以不能用that, that只能起到连接作用，不能做主语。