However, when you read totally new stories for you, you may spend
much of concentration on it, because you just want to know what will happen next. You just try to keep concentration way more on the story itself. In that case, sometime I notice that my mind gets full of English because Japanese wouldn’t be of any help to me and there’s no room which any Japanese can get into.

And I sometimes feel like that this sort of consentration would form up some kind of wonderous power which can get over the problems of vocaburaly or grammers easily. It’s very hard to explain with words, but I feel like such concentration has a great power even to make up a new part in the brain, to think in English for me.

Well, anyways, I think there’s no proper answer to this question because there’s a good point on each of the ways.

Sorry if this comment just made you confused….^^;)
Maybe, all what I can say for sure is, “Let’s keep reading lots of and many kinds of stories with fun!”. ^^