He is going to buy a useful book.

他打算买一本有用的书。

youdao

I have a useful book. It is about how to play basketball.

我有一本有用的书。它是关于如何打篮球的。

youdao

It is a useful book.

这是一本很实用的书。

youdao

So, Hobbes clearly believes or thinks that this will be a useful book for a sovereign to read and hoping it will gain the ear of a sympathetic sovereign or potential sovereign.

很明显，霍布斯认为,这对君王将是本很有用的书,并真心希望它能得到一些富有同情心的君王,或是即将接任的君王的欣赏。

耶鲁公开课 - 政治哲学导论课程节选

Again, I apologize for going too fast but it's still a useful exercise I think, so have a look at it in the book.

再次,我为我讲得太快而道歉,但它仍然是个有用的练习,所以要好好看看课本中的内容

耶鲁公开课 - 博弈论课程节选

This is a useful book for people looking to start a professional speaking career.

FORBES: Resolved to Start a Speaking Career in 2012? A Roundup of Recent Books To Help You Get Cranking

The references to the founders and the documents in the second half of the book make it a useful book to have on the shelf.

FORBES: Nullification Should Be Taken Seriously, Not Caricatured

Some of this story is told in a patchy but useful book by Herbert Inhaber, Why Energy Conservation Fails (Quorum, 1997).

FORBES: Insights: The energy diet that flopped