[Grammar] let alone ++ bare infinitive or infinitive?

[murattopak]

It is often impossible to walk down the aisle to get to the toilets, let alone ..... exercise.

a- taking
b- to take
c- take

Correct answer here is "to take".

Now I am wondering if I can say that the verb going with "let alone" follows the structure of previous verb form.

For example
She can't boil potatoes, let alone cook a meal
bare infinitive--- let alone bare infinitive

For my question above
to get to---- let alone to take

But I have no idea how to form the verb after a past simple,a past perfect, and a present perfect sentence.
And also after passives...
The problem wasn't discussed, let alone ////solved// to be solved// being solved// Which one fits here?

Is there any general rule for the usage of "let alone"?
Thanks in advance.

 

[Tdol]

Let alone does not dictate which verb form follows it. It should be the same as the one that it relates to, so in the first question you have the infinitive because that's what you're using and in the second you're using the past participle to make a past passive- wasn't discussed...solved.