iCloud space getting finished on account of iBooks

Unfortunately I did the mistake of turning on iCloud for iBooks and now I find that the entire 5GB is close to being finished.

Is there any way I can download the books from iCloud so that in case I switch off the setting at the device ,the books are not lost ?
If I delete books from the iCloud iBooks , will they also get deleted from the physical device where they have been already downloaded ? One possible pre-requisite I can think of is to first disable iBooks in iCloud on my various devices (iPad/iPhone/Mac) and then carry out deletion via Setting option of any iO

最后更新：2017-10-06 17:47:57