For many people around the world, a subway journey means speeding from one dull station to the next, surrounded by too many uncomfortable, impatient people. But on the Moscow Metro, taking the subway is like walking through a national heritage site. Depending on where you get off, you'll receive a brief course in architectural movements and face colorful glass windows, marble(大理石) columns, gilded(鎏金的) mosaics and painted scenes from Russian history.

    “These extraordinarily beautiful places are unlike any metro station I've ever seen, “says Vancouver-based photographer David Burdeny.

    When Burdeny, who himself has a master's degree in architecture, first found out about Moscow's metro stations, he was struck by the work of art. In all, he has photographed 20 of the most beautiful stations.

    Burdeny had originally planned to focus on Russian stations more generally, taking photos of examples in both St. Petersburg and Moscow.

    “But when I saw the stations in Moscow, they just completely blew away the St. Petersburg ones,” he says.

    Shooting in the subway sounds simple, but it is not without challenges. For one thing, Burdeny had to figure out a way to access them between 00:30 a.m. and 5:30 a.m., when the stations were closed.

    In the end, he settled on Arbatskaya Metro Station, whose vaulted(拱状的) arches he found the most beautiful. But it also represented a challenge he was not sure if he was able to overcome: conveying the hugeness of the spaces. The Arbatskaya platform, for example, stretches 820 feet.

    “Some of the arches are quite long,” he says. “When you enter them, they're just so completely grand.”

函数y=$\frac{3}{x}$与y=x﹣1图象的一个交点的横、纵坐标分别为a、b，则$\frac{1}{a}$﹣$\frac{1}{b}$的值为（　　）

     My parents used to tell me how important school was for me, but I didn't think so. I paid little attention to it. But one thing let me finally 1 what my parents meant.
     One day, when I   2   a mobile phone store, I saw an advertisement on its door. It was hiring new workers!
“Sir, are you hiring people?” I went   3  the shop and asked. “Yes, but you should be the man who we need,” the manager answered. He looked at me for a few   4 from head to foot. “Do you have a high school diploma(文凭)?” 5 he, “Or do you have any work experience?”
    I felt so ashamed and  6 that I didn't know what to say, so I just turned around and left. I could not fall asleep that night, and I thought a lot about my  7  . “I must go to school or I can’t do anything without a good education,” I  8 to myself silently. I never went back to the store again 9 I finished my study and got a diploma.
10 looked the same when I returned to the store: the same people and the same design. However, compared with last time, I had more  11  . The manager told me they needed new    12  . So it was a great chance for me.
    I 13  my diploma to the manager. He looked at it and said, “Great, you are in.”
    Now I am still working in the same store. With this experience, I always  14 people to attend school. Education helps you have a bright future. Now I am not worried about my future because I'm still   15in my spare time.

下列词语中划线的字，每对读音都不相同的一组是(　　)