如图，在三棱台ABO﹣A₁B₁O₁中，侧面AOO₁A₁与侧面OBB₁O₁是全等的直角梯形，且OO₁⊥OB，OO₁⊥OA，平面AOO₁A₁⊥平面OBB₁O₁，OB=3，O₁B₁=1，OO₁= $\sqrt{3}$ ．

    Today is Friday. Peter has six classes today. He goes to school at 7:30 a.m. At 8:00 a.m., he begins his first class. The first class is English. At 9:00 a.m., he has math. Peter likes math because it’s interesting. At 10:00 a.m. she has a biology class. Peter thinks it's very boring. Then at 11:00 a.m., he has a history class. That's his favorite subject. He can learn a lot about the past from history.
    Peter has lunch at school at about 12:00. Then he has a short break. At 1:30 p.m., he has a music class. At 2:30 p.m., he has a P.E. class. Peter likes this afternoon, because music and P.E. are easy and interesting. School is over at 4:00 p.m. Peter is happy because he can go home and have a good time on Saturday and Sunday.
阅读短文内容，选择正确答案。

If you have a holiday, why not ________ on a trip?

如图，三棱柱ABC﹣A₁B₁C₁中，侧面BB₁C₁C为菱形，AB⊥B₁C．

（Ⅰ）证明：A₁C₁=AB₁；

（Ⅱ）若AC⊥AB₁，∠BCC₁=120°，AB=BC，求二面角A﹣A₁B₁﹣C₁的余弦值．

阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。（共10小题；每小题1.5分，满分15分）

    In 1863 the first underground passenger railway in the world opened in London. It ran for just under seven kilometers and allowed people to avoid terrible ____ (crowd) on the roads above as they travelled to and ____ work. It took three years to complete and was built using an interesting method. This included digging up the road, ____(lay) the track and then building a strong roof over____ top. When all those had been done, the road surface was replaced.

    Steam engines ____(use) to pull the carriages and it must have been____(fair) unpleasant for the passsengers, with all the smoke and noise. However, the railway quickly proved to be a great success and within six months, more than 25,000 people were using____every day.

    Later, engineers ____(manage) to construct railways in a system of deep tunnels (隧道）, which became known as the Tube. This development was only possible with the ____(introduce) of electric-powered engines and lifts. The central London Railway was one of the most ____(success) of these new lines, and was opened in 1900. It had white-painted tunnels and bright red carriages, and proved extremely popular with the public.