YOU SAID:
a bird can fly but a fly cannot bird
INTO JAPANESE
鳥は飛ぶことができますが、ハエは鳥を飛ばすことができません
BACK INTO ENGLISH
Birds can fly, but flies cannot.
INTO JAPANESE
鳥は飛ぶことができますが、飛ぶことはできません。
BACK INTO ENGLISH
Birds can fly, but they cannot.
INTO JAPANESE
鳥は飛ぶことができますが、飛べません。
BACK INTO ENGLISH
Birds can fly, but they cannot.
That didn't even make that much sense in English.