Possible conjugations on certain grammar patterns


On _"A Dictionary of Basic Japanese Grammar"_ , when a grammar pattern works
with the informal form of a verb, they only talk about the positive present
tense and the positive past tense. (At least until page 131, which is where
I'm currently in). I think it's just the way this book works, but I'm not
absolutely sure.

For example:

Could...

> 雪子さんとはデートしただけです。

...be...

> 雪子さんとはデートできないだけです。

?

* * *

Or could...

> あの人はよく勉強するだけではなくよく遊びます。

...be...

> あの人はあまり勉強しないだけではなくあまり遊びません。

?

* * *

By the way, when we use informal adjectives, could I write...

> この家は大きくないだけです。

...or can't I use the negative form?

* * *

The same question for な-adjectives. Can I say:

> このお菓子は色がきれいじゃないだけです。

?

* * *

Basically, my question is: whenever I see _"Vinf"_ (informal verb) or _"Adj
(i) inf"_ (informal い-adjective) on this book, can I assume it's **every**
informal form?




ない behaves like an i-adjective. You may end up with some strange sentences
(雪子さんとはデートできないだけです, but you can turn water into wine) but grammatically you
can do what you are suggesting.

