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I'm familiar with the てもいい form to ask for permission to do something in the
future. For instance:

> Is it okay if I eat the candy?

> 菓子を食べてもいいか。

How would I ask if something I did already in the past was permitted? I
thought to change いい to よかった but wasn't sure if that would have the right
meaning. For example, I'd like to say:

> Was it okay that I ate the candy?
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2021-04-16T03:36:23.643
86159
2021-04-17T03:02:47.270
43596
question
て-form past permission
How to ask if an action in the past was permissible?
For the sake of this answer, your sentence

> Was it okay that I ate the candy?

can be rephrased as

> Was I _allowed_ to eat the candy?

It doesn't change the meaning of the original sentence. You want to ask if
eating candy was permissible.

The only grammar construction I can think of that suits your needs is
[V-causative]+くれる. When you use this construction, it conveys the nuance that
someone allowed/let you do something. For example, if you want to say that
someone allowed you to eat, you say

> 食べさせてくれた

Now back to your question, "Was I allowed to eat the candy?" can be understood
in Japanese as

> 菓子を食べさせてくれた?

Hope it helps.
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2021-04-16T05:06:42.653
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As you suggested in your question, the past form of ～て(も)いい can be formed
using the よかった. For example,

> 子供のとき、コーヒーを飲んでもよかった。  
>  When I was I child, I was allowed to drink coffee.

So, I don't see a reason why this shouldn't work for your example.
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2021-04-17T00:12:29.980
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> お菓子を食べても良かったですか？  
>  お菓子を食べても大丈夫でしたか？
>
> Was it okay to eat the candy?

This is already grammatically correct, but it says nothing about whether the
speaker actually ate it or not. If you need to tell you actually ate it, you
can say something like:

> お菓子を食べたんですが、良かったですか？  
>  お菓子を食べてしまいましたけど大丈夫でしたか？

* * *

Also note that いいか, よかったか and so on without です/ます are unrealistically blunt
and impolite. Avoid it unless you can behave like a tyrant. In casual
settings, you should use the rising intonation ("いい?" or "よかった?") instead of
か.
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2021-04-17T00:24:35.103
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