This doesn't have to be too big of a shortcoming; previously mentioned Calibre fully supports converting one format to another, and Gutenburg offers most books in EPUB.

这也不算是非常大的缺点，之前提到的Calibre完全支持转换一种格式到其他格式，并且古登堡提供的电子书大多是epub格式。

youdao

In April 1992, equipped with little more than a .22 calibre rifle and a 10lb bag of rice, he headed into the Big Empty of the Alaska wilderness, near Fairbanks, not far from Mount McKinley.

BBC: Call of the wild