每个案件被法庭受理前,都必须附上受理这份案件的原因。
少了个逗号,原句应该是这样的:
As each case was decided by an appellate court,an opinion was writtrn,giving the reasons why the case was decided.
前面应该很好理解,就不解释了。
giving the reasons why the case was decided 这句话是用来修饰opinion的,表示这个opinon的目的(是为了提供案件受理的原因)。
有疑问可以追问。