YOU SAID:

I was disappointed because my results dropped suddenly.

INTO JAPANESE

成績が急に下がったのでがっかりしました。

BACK INTO ENGLISH

I was disappointed because my grades dropped so quickly.

INTO JAPANESE

成績がすぐに下がったのでがっかりしました。

BACK INTO ENGLISH

I was disappointed because my grades went down so quickly.

INTO JAPANESE

成績がすぐに下がったのでがっかりしました。

BACK INTO ENGLISH

I was disappointed because my grades went down so quickly.