one question from Princeton

shazhi

Much of the garbage that might otherwise be dumped in  landfills in the past is now being recycled.

Ans:that might otherwise have been dumped in landfills

请问，为什么原句不对，为什么正确答案中不见了in the past?

braveMBA

感觉象是对过去发生的虚拟语气，所以应该是HAVE BEEN。至于in the past的作用不大，因为句子已经表达了这个意思，加上也可，不影响句子意思。