this year's electricity consumption is almost the same as th

this year's electricity consumption is almost the same as that of last year,though at the end of this year,and comparing with the same period of last year.4565
想知道的语言点：1—the same as 的意思 2— the same as that 中的that指代的是什么3— that of 为什么有of 4—same period of last year
the same as that 中that指代this year's electricity consumption
因为是 electricity consumption of this year，所以用of