YOU SAID:

Flying dogs are the most difficult thing to kill.

INTO JAPANESE

飛行犬を殺すために最も困難な事であります。

BACK INTO ENGLISH

Flying dog to kill is the most difficult thing.

INTO JAPANESE

飛行犬を殺すためには、最も困難なものです。

BACK INTO ENGLISH

Most difficult thing is to kill the flying dog.

INTO JAPANESE

最も困難な事は、飛行犬を殺すことです。

BACK INTO ENGLISH

The most difficult thing is killing the flying dog.

INTO JAPANESE

最も困難な事は、飛行犬を殺しています。

BACK INTO ENGLISH

The most difficult thing kills a flying dog.

INTO JAPANESE

最も困難な事は、飛行犬を殺します。

BACK INTO ENGLISH

The most difficult thing kills flying dog.

INTO JAPANESE

最も困難な事は、飛行犬を殺します。

BACK INTO ENGLISH

The most difficult thing kills flying dog.