Why is そんなに the best answer in「（いくら・そんなに・どんなに）笑わなくてもいいじゃありませんか。」?


Consider the following question from 新完全マスター文法 (N3):

> （ ）笑わなくてもいいじゃありませんか。
>
> a いくら
>
> b そんなに
>
> c どんなに

According to the theory associated with the exercise:

いくら should be followed by ～ても／～でも

そんなに should be followed by ～ない

どんなに should be followed by ～ても／～でも

However, when we look at the question above, the example sentence includes
_both_ ～ても and ~ない. According to the answer key, そんなに is the best answer...
but why?




Well, this may not be a very good question if there is not enough prior
context. Saying いくら/どんなに笑わなくても is also perfectly grammatical, and actually
makes sense in a certain context.

>   * そんなに笑わなくてもいいじゃありませんか。  
>  You don't have to laugh like that.  
>  (Please, don't laugh at me like that!)
>   * いくら笑わなくてもいいじゃありませんか。  
>  どんなに笑わなくてもいいじゃありませんか。  
>  No matter how [someone] won't laugh/smile, that's okay, isn't it?  
>  (Being unwilling to smile is not a problem, huh?)
>

The latter would make sense, for example, when you are protecting a person who
stubbornly refuses to smile in front of a TV camera.

Still, in a test like this, you are expected to give the most "likely" answer,
so I will definitely choose そんなに if I had to choose one.




Well, this may not be a very good question if there is not enough prior
context. Saying いくら/どんなに笑わなくても is also perfectly grammatical, and actually
makes sense in a certain context.

>   * そんなに笑わなくてもいいじゃありませんか。  
>  You don't have to laugh like that.  
>  (Please, don't laugh at me like that!)
>   * いくら笑わなくてもいいじゃありませんか。  
>  どんなに笑わなくてもいいじゃありませんか。  
>  No matter how [someone] won't laugh/smile, that's okay, isn't it?  
>  (Being unwilling to smile is not a problem, huh?)
>

The latter would make sense, for example, when you are protecting a person who
stubbornly refuses to smile in front of a TV camera.

Still, in a test like this, you are expected to give the most "likely" answer,
so I will definitely choose そんなに if I had to choose one.

