Because + so ?

[betterin]

"Because it is going to rain, so we had better leave early."

Although "so" is redundant, is this sentence grammatically correct because so can be an adverb?

[Humble]

Hi, Betterin,
Your sentence will be OK if you leave out either because or so.
Rgs

[betterin]

Is this sentence grammatically correct if both "because" and "so" are used?

[Humble]

I don't think so.

[betterin]

I think that it is at least grammatically correct if both "because" and "so" are used, although "so" is redundant.

[Humble]

No, definitely not.

[betterin]

I think it is OK,because "so" can be considered as an adverb.

[Lynque]

An inversion would clear things up: "We had better leave early, because it is going to rain."

With this, it's easy to see how 'so' is redundant in either structure.

[Tdol]

I think it is OK,because "so" can be considered as an adverb.

In what sense? What's it modifying?

[Lynque]

All so is doing is "coordinatingly joining" the clauses, and there you are.