Beside those trees is my house.
我家在那些树木的旁边.
my house 是主语,is是谓语动词,beside those trees是介词短语作表语.
不能写成those trees beside...
如果一定要改,则改成：
Those trees are beside my house.
那些树木在我家旁边.
主语换成trees,谓语动词也要改成复数第三人称are.