Vector3 acc = Vector3.zero;
            Vector3 diff;
            if (Input.GetKey(KeyCode.LeftArrow))
            {
                acc.x = -0.1f;
                transform.localScale = new Vector3(-1, 1, 1);
            }
            if (Input.GetKey(KeyCode.RightArrow))
            {
                transform.localScale = new Vector3(1, 1, 1);
                acc.x = 0.1f;
            }
            diff = Vector3.MoveTowards(transform.localPosition, transform.localPosition + acc, 0.5f * Time.time);
            diff.y = transform.localPosition.y;
            diff.z = 0;
            //设置边界
            if (diff.x < leftBorder)
            {
                diff.x = rightBorder;
            }
            if (diff.x > rightBorder)
            {
                diff.x = leftBorder;
            }
            transform.localPosition = diff;