void Update()
  {
      float hor = Input.GetAxis("Horizontal");
      float ver = Input.GetAxis("Vertical");
      var dir = new Vector3(hor, 0, ver);

      // 方式1
      //transform.position += dir * Time.deltaTime * 2f;

      // 方式2
      transform.Translate(dir * Time.deltaTime * 2f);

  }