Hey Hideki,
Don't beat yourself up. I can't imagine what's it's like trying to learn a whole different alphabet, let alone language!
In "refrigerator", there's two parts which have particular emphasis, the "re" at the beginning and the "g". There's a very hard "g" in "refrigerator". If I were trying to learn the word all over again, I'd break it down into it's syllables. In "refrigerator", there are four syllables, "re - frig - er - ator".
I hope that helps!
Try and break it down if you can, but put like I say, put particular emphasis on the "re" and the "g".