换一种写法，我的npoi版本不支持document.Paragraphs

如果你的NPOI版本不支持 `document.Paragraphs`，可以使用下面这种方式来实现Word文档的复制：

using (FileStream stream = new FileStream("path/to/your/document.docx", FileMode.Open, FileAccess.ReadWrite))
{
    XWPFDocument document = new XWPFDocument(stream);

    // 创建新的Word文档并将原始文档的内容复制到其中
    XWPFDocument newDocument = new XWPFDocument();
    foreach (IBodyElement element in document.BodyElements)
    {
        if (element.ElementType == BodyElementType.PARAGRAPH)
        {
            XWPFParagraph paragraph = (XWPFParagraph)element;
            XWPFParagraph newParagraph = newDocument.CreateParagraph();
            newParagraph.Alignment = paragraph.Alignment;
            foreach (IRunElement run in paragraph.Runs)
            {
                if (run.ElementType == RunElement.TAB)
                {
                    newParagraph.CreateRun().AddTab();
                }
                else if (run.ElementType == RunElement.TEXT)
                {
                    XWPFRun newRun = newParagraph.CreateRun();
                    newRun.SetText(run.Text);
                    newRun.IsBold = run.IsBold;
                    newRun.IsItalic = run.IsItalic;
                    newRun.IsStrikeThrough = run.IsStrikeThrough;
                    newRun.IsUnderline = run.IsUnderline;
                    newRun.FontFamily = run.FontFamily;
                    newRun.FontSize = run.FontSize;
                    newRun.SetTextHighlightColor(run.GetHighlightedColor());
                    newRun.SetColor(run.GetColor());
                }
            }
        }
        else if (element.ElementType == BodyElementType.TABLE)
        {
            // 处理表格
        }
    }

    // 将新文档保存
    using (FileStream newStream = new FileStream("path/to/new/document.docx", FileMode.Create, FileAccess.ReadWrite))
    {
        newDocument.Write(newStream);
    }
}

这种写法通过遍历文档中的 `BodyElements` 来获取段落和表格等元素，然后逐一复制到新文档中。需要注意的是，这种方法在处理表格时需要进行额外的处理，可以参考NPOI的官方文档进行实现。