YOU SAID:
The marshy fields are caused by rain
INTO JAPANESE
沼地の畑は雨によるものである
BACK INTO ENGLISH
the swampy fields are caused by rain
INTO JAPANESE
沼沢地は雨によって生じる
BACK INTO ENGLISH
the swamps are created by rain
INTO JAPANESE
沼地は雨によってできている
BACK INTO ENGLISH
the marshlands are formed by rain
INTO JAPANESE
沼地は雨によって形成される
BACK INTO ENGLISH
the marshlands are formed by rain
Come on, you can do better than that.