NetCore Extend类无法重新实现方法

Question

我使用Net Core 2.2，请帮助我在.net中扩展 我有

interface IBaseService<TDataContext, TEntity>
{
    TEntity Insert(TEntity objectToInsert);
    TEntity Update(TEntity objectToInsert);
}

Class BaseService<TDataContext, TEntity>:IBaseService<TDataContext, TEntity>
{
    public TEntity Insert(TEntity objectToInsert) {
        /*action Insert in BaseService */
    }
    public TEntity Update(TEntity objectToInsert) {
        /*action Update in BaseService */
    }
}

interface IUserService<TDataContext, TEntity>:  IBaseService<TDataContext, TEntity>
{
    TEntity SEARCH(TEntity objectToInsert);
}

如何使用UserSerice和IUserService扩展类，而不实现更新，插入，仅实现新方法SEARCHIn类

Class UserSerice<TDataContext, TEntity>:IUserService<TDataContext, TEntity>
{
    public TEntity Search(TEntity objectToInsert){
           /*SEARCH ACTION*/
    }

    //I want use action Insert / Update in BaseService
    /*
        public TEntity Insert(TEntity objectToInsert);
        public TEntity Update(TEntity objectToInsert);
    */
}