YOU SAID:

I was sitting behind the tree, when I saw a bird flying with a knife

INTO JAPANESE

ナイフで飛んでいる鳥を見たとき、私は、木の後ろに座っていた

BACK INTO ENGLISH

When I saw the bird with a knife, I was sitting behind the trees

INTO JAPANESE

私は木の後ろに座っていたナイフで鳥を見て、

BACK INTO ENGLISH

I saw a bird with a knife was sitting in the back of Thursday,

INTO JAPANESE

木曜日、後ろに座っていたナイフで鳥を見た

BACK INTO ENGLISH

Saw a bird with a knife Thursday, was sitting in the back

INTO JAPANESE

木曜日ナイフで鳥を見て、後ろに座っていた

BACK INTO ENGLISH

Bird watching on Thursday with a knife, was sitting in the back

INTO JAPANESE

後ろに座っていたナイフで木曜日にバードウォッチング

BACK INTO ENGLISH

With the knife sat in the back on Thursday birding

INTO JAPANESE

木曜日バードウォッチングの後ろに座っていたナイフで

BACK INTO ENGLISH

Thursday was sitting in the back of the bird knife

INTO JAPANESE

木曜日は鳥ナイフの後ろに座っていた

BACK INTO ENGLISH

Thursday was sitting in the back of the bird knife