这段C# 代码可以帮我注释下么？或者说翻译下 谢了

private void label1_MouseDown(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                downPoint = e.Location;
                downRectangle =
                    new Rectangle(0, 0, ((Control)sender).Width, label1.Height);
                downRectangle.Offset(((Control)sender).PointToScreen(new Point(0, 0)));
                ControlPaint.DrawReversibleFrame(
                    downRectangle, Color.White, FrameStyle.Thick);
                lastRectangle = downRectangle;
            }
        }

        private void label1_MouseUp(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                ControlPaint.DrawReversibleFrame(
                    lastRectangle, Color.White, FrameStyle.Thick);
                    label1.Location = new Point(
                    ((Control)sender).Location.X + e.X - downPoint.X,
                    ((Control)sender).Location.Y + e.Y - downPoint.Y);
            }
        }

        private void label1_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                ControlPaint.DrawReversibleFrame(
                    lastRectangle, Color.White, FrameStyle.Thick);
                Rectangle rectangle = downRectangle;
                rectangle.Offset(e.X - downPoint.X, e.Y - downPoint.Y);
                ControlPaint.DrawReversibleFrame(
                    rectangle, Color.White, FrameStyle.Thick);
                lastRectangle = rectangle;
            }
        }

 鼠标左键单击事件。设置一个label。里面的方法，你去VS里面看。