YOU SAID:

sophie is good a throwing a pencil

INTO JAPANESE

ソフィーは鉛筆を投げるのが上手い

BACK INTO ENGLISH

Sophie's good at throwing pencils.

INTO JAPANESE

ソフィーは鉛筆を投げるのが得意だ。

BACK INTO ENGLISH

Sophie is good at throwing pencils.

INTO JAPANESE

ソフィーは鉛筆を投げるのが得意だ。

BACK INTO ENGLISH

Sophie is good at throwing pencils.