Now here's what I call a turn-up for the books - a film star's been giving away free books on the London Underground. If you're a bookworm, a Harry Potter fan and a London Underground user then it's been an exciting month for you.

Emma Watson, who starred in films based on the novels about a fictional schoolboy wizard, has been hiding books on the Tube for passengers to leaf through.

It's part of the Books On The Underground movement, which has a simple aim: to get more people burying themselves in literature. And the way they do it is to leave tomes on trains for commuters to pick up, dip into and then leave for another lucky reader to skim.

The movement started out in 2012 and drops off about 150 volumes a week in stations across the UK's capital. Talking about Watson's participation in the project, the manager of Books On The Underground, Cordelia Oxley, said, "The reaction has been phenomenal. It must be a mixture of how much everyone adores Emma, and how exciting it is to find something as wonderful as a new book on your journey."

The 100 or so editions Watson left for passengers to pore over were even more special because she left a hand-written inscription. The paperbacks were copies of Kaya Angelou's Mom & Me & Mom.

One person who discovered a copy of the book on the Tube said she felt like the character Charlie Bucket – a boy who finds a golden ticket to the world's greatest chocolate factory – in the Roald Dahl classic, Charlie and the Chocolate Factory.

Watson became a UN Women Goodwill Ambassador in the summer of 2014 and has since started devouring as many books and essays on equality and feminism as possible. She has also started her own book club.

So, why not take a leaf out of Emma Watson's book and leave a copy of your favourite book on a train? It could make a stranger's life richer. 

词汇表

a turn-up for the books 意想不到的事情，出乎意料的事
a bookworm 书虫，书迷
based on 以……改编的
a novel 小说
fictional 虚构的
to leaf through 略读，浏览
to bury oneself (in something) 把自己埋在（某物）中
a tome 巨著
to dip into 随便翻翻
to skim 粗略地浏览
a volume 书；卷，册
an edition 版本
to pore over 仔细阅读
hand-written 手写的
an inscription 题赠，题词
a classic （书）经典作品
to devour 如饥似渴地阅读
an essay 散文，短文
a book club 读书俱乐部
to take a leaf out of someone's book 以某人为榜样，向某人学习