YOU SAID:
I heard that mark can’t sleep
INTO JAPANESE
そのマークは眠れないと聞いた
BACK INTO ENGLISH
I heard Mark couldn't sleep.
INTO JAPANESE
マークは眠れないと聞いた。
BACK INTO ENGLISH
I heard that Mark couldn't sleep.
INTO JAPANESE
マークは眠れないと聞いた。
BACK INTO ENGLISH
I heard that Mark couldn't sleep.
That didn't even make that much sense in English.