几道sat语法题求解

I will always remember (you) standing by me offering me encouragement.
you改your,为什么you不可以?you作宾语,standing by 和offering 作宾补

   2.In 1986,a radiation lasts for the better part of a year.
       这个是改编的,这里的better part of a year要怎么翻译?
   3.Because of the storm,the farmers are doing half of the business that they are doing (previous) to the land.
       这题也是改的,previous没错,但为什么改previously不行?修饰doing
  4.（Was） （it） （they） who were involved in last week's （unruly） demonstration?
      答案是句子没错,it they这三个是什么成分,我觉得是Were they who..