Joanrry琼
答案：successful that it was paid much attention to．结合句意和so用so…that表示如此…以至于，successful成功的，关注pay attention to，much修饰表示程度，主语it是pay attention to的承受者，结合主句是一般过去时，故用一般过去时的被动语态was/were+过去分词，主语it故was，pay的过去分词paid，故答案是successful that it was paid much attention to．
