题干

如图所示,质量为10kg的物体,在水平地面上向左运动.物体与水平面间的动摩擦因数为0.2.与此同时,物体受到一个水平向右的推力F=20N的作用,则物体的加速度为(g取10 m/s2)(     )

A:0

B:4 m/s2,水平向右

C:2 m/s2,水平向右

D:2 m/s2,水平向左

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B

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完形填空

    When my wife and I decided to open our bookstore in 2012, we were a little 1.

    The challenges facing small bookstores were—and remain— 2. Aside from the obvious 3 in online selling, the increase in the popularity of e-books has had a(n)4 effect on independent providers.

    The question is why a new, small-scale(小规模的)provider would 5 enter such a(n)6 market?

    From a personal view, our reasoning was sound: we wanted to 7 our love of great books and reading for pleasure with as many 8 people as possible.

    Having done our homework, one thing became 9. In order for us to succeed, we would have to offer something that none of our larger competitors already provided.

    And so we 10 the Willoughby Book Club. We set up our website in the summer of 2012—and we haven't looked back.

    The idea of 11 is simple. We offer a range of book subscription gift packages, 12 in three-, six- and 12-month options. Our customers 13 a package, tell us a little about the person they're buying it for, and we use this information to 14 the(接收者)a hand-picked, gift-wrapped(包装的)book once a month.

    We also recently decided to 15 one new book to Book Aid International for every gift subscription sold. These books are sent out to sub-Saharan Africa, 16 the educational work there.

    Within four months of starting out, we won the Young Bookseller of the Year award at the 2013 Bookseller awards.

    Our brief 17 from new booksellers to award receivers has been challenging and 18. The biggest thing we've learned is that, despite the 19 facing independent providers, there is a 20 for then in the UK market. It's just a question of finding it.