public class FieldExamination:EntityRoot

{

   public string FId{get;set;}

   public Datetime BeginTime{get;}

   public Datetime ProcessTime{get;}

   //獲取本場考試的試卷

   public  GetCurrentExBook(string stuId){//……}

   //本場考試的負責人

   public Employee  Principal{get;}

   public Subject  CurrentSubject{get;}

}

public class FieldExaminationRepostiroy:Repository<FieldExamination>

{

  public FieldExamination GetById(string id){//……}

}