YOU SAID:
the eagle knew he had to swim
INTO JAPANESE
ワシは彼が泳ぐ必要があることを知っていた
BACK INTO ENGLISH
Eagle knew that he needed to swim
INTO JAPANESE
イーグルは彼が泳ぐ必要があることを知っていた
BACK INTO ENGLISH
Eagle knew that he needed to swim
That didn't even make that much sense in English.