range中的i会自动递增，除非您愿意，否则您不必使用i = i + 1。
你就迭代了两次。

bookshelf = {'name':['1', '2'], 'author': ["First", "Second"]}

if __name__ == '__main__':
    for i in range(len(bookshelf.get('name'))):
        print(bookshelf['name'][i])
        print(bookshelf['author'][i])

我尝试了以下方法：

bookshelf={'A':['A1','A2'],'B':['B1','B2']}
for i in range(0,2):
    print(f"The name of the book is {bookshelf['A'][i]}, the name of the author is {bookshelf['B'][i]} ")

此问题不需要key，value命令。