这个苹果又红又圆，可以说：

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.

（Ⅰ）求函数f（x）的最小正周期和单调递增区间；

（Ⅱ）若x∈0， $\frac{\pi }{2}$ ，且f（x）= $\frac{1}{3}$ ，求cosx的值．