[求助]Prep21题怎么写？

各位XDJM，小女刚刚接触GMAT，请问这个题目怎么写啊？望前辈们指点啊，万分感激！

All personnel evaluations at a company should be multi-directional ?that is, people at every level of the

organization should review not only those working 'under' them but also those working 'over' them.