我忘記多少錢了 請問英文 I forgot how much it is 對嗎 謝謝?

I forgot how much it cost.

超簡易:

I forget how much it was.

要用was因為是以前的費用.
要用forget因為是現在還忘記.

要是現在已經又記起來了(或是經過別人的提醒)的話,就可以用過去式.

I forgot how much that had been charged---------passive and past perfect tense.
Or
I forgot how much it costed.
----the price that should be charged (for something)

I forgot how much is it. Yip

I've forgotten how much does it cost.