Hundreds of years ago,life was much harder than it is today.这句话为什么要加it is?直接写than today不行吗

Hundreds of years ago,life was much harder than it is today.这句话为什么要加it is?直接写than today不行吗
Hundreds of years ago,life was much harder than it is today.这句话为什么要加it is?直接写than today不行吗

Hundreds of years ago,life was much harder than it is today.这句话为什么要加it is?直接写than today不行吗
因为对比的不是today 而是today's life