Because it is a book with answers to many other questions like the fastest bird in Europe。
句意:為什么比弗爵士認(rèn)為吉尼斯世界紀(jì)錄是個好主意?
根據(jù)文章第二段Sir Beaver thought that there must be many other questions like this, but there was no way to find the answer. He realized that a book with answers like this may be a good idea. He was right!(爵士想到一定還有很多這樣的問題,但是沒有辦法找到答案。他意識到一本有這樣答案的書可能是個好主意。他是對的!)可知,原因是這本書有很多答案。故填
Because it is a book with answers to many other questions like the fastest bird in Europe.