YOU SAID:

I'm going to lose my marbles

INTO JAPANESE

私はビー玉を失うつもりです

BACK INTO ENGLISH

I'm going to lose a marble

INTO JAPANESE

私は大理石を失うつもりです

BACK INTO ENGLISH

I am going to lose the marble

INTO JAPANESE

私は大理石を失うつもりです

BACK INTO ENGLISH

I am going to lose the marble