let alone/not to mention

[angliholic]

He can't read, let alone/not to mention write.
We can't afford a car, not to mention/let alone the fact that we have no garage.
He has a big house and an expensive car, let alone/not to mention a villa in France.


Is let alone interchangeable and synonymous with not to mention in all contexts? Thanks.

[Naamplao]

He can't read, let alone/not to mention write.
We can't afford a car, not to mention/let alone the fact that we have no garage.
He has a big house and an expensive car, let alone/a villa in France.


Is let alone interchangeable and synonymous with not to mention in all contexts? Thanks.

He can't read, let alone write.

We can't afford a car, not to mention the fact that we have no garage.

He has a big house and an expensive car, not to mention a villa in France.

I cannot explain why but these sound better to me. It seems that you use "let alone" if it is followed by a verb and "not to mention" if followed by a noun. That may be coincidence though.

[angliholic]

He can't read, let alone write.

We can't afford a car, not to mention the fact that we have no garage.

He has a big house and an expensive car, not to mention a villa in France.

I cannot explain why but these sound better to me. It seems that you use "let alone" if it is followed by a verb and "not to mention" if followed by a noun. That may be coincidence though.

Thanks, Naamplao, for the correct choice and reply.
I checked up on the samples in my dictionary again to make sure if they match what you describe. Yeah, you can that again in most cases, but there are some exceptions. For example,

There isn't enough room for us, let alone/not to mention six dogs and a cat.

Which will you use in the above context? Sorry! I'll give you the answer later to see if this goes well with your English instinct--I mean every native speaker of course.

[Naamplao]

Thanks, Naamplao, for the correct choice and reply.
I checked up on the samples in my dictionary again to make sure if they match what you describe. Yeah, you can that again in most cases, but there are some exceptions. For example,

There isn't enough room for us, let alone/not to mention six dogs and a cat.

Which will you use in the above context? Sorry! I'll give you the answer later to see if this goes well with your English instinct--I mean every native speaker of course.

There isn't enough room for us, let alone six dogs and a cat.

[angliholic]

Thanks, Naamplao, for the correct gut feeling.

But could you write down the rules of this usage?

[Naamplao]

Thanks, Naamplao, for the correct gut feeling.

But could you write down the rules of this usage?

Sorry...I cannot come up with a rule...my first guess at a rule fell apart with this last example. All I can say is one way sounds better than the other...and I know this is not a good explanation for you.

[angliholic]

Thanks, Naamplao.
Maybe someone will come up with a sensible and reasonable rule later on.