has so much been done
原因：
如果句子以never,only,seldom等否定含义或者半否定含义的副词开头,那么后面的句子应该采取部分倒装.
本句采取的是现在完成时态,正常的表达应该是
So much has been done for the teacher.
这里要倒装 因此是 has so much been done for the teacher.