At the broadest level, you can specify a root element of set when including two or more books; for example, a whole reference collection.

在最高级别上，可以在包括两个或多个books(例如整个参考资料集合)时指定根元素set。

youdao

At the broadest level, you can specify a root element of set when including two or more books; for example, a whole reference collection.

在最高级别上，可以在包括两个或多个books(例如整个参考资料集合)时指定根元素set。

youdao