A、Capitol Hill--the Washington Monument--the White House. B、The Capitol Building--the National Gallery--the Washington Monument.

I hope you all enjoyed your visit to Capitol Hill. If you look back behind you, you can get an excellent look at the Capitol Building, with its beautiful dome and the Statue of Freedom on top. I forgot to mention that the design for the original building was chosen by George Washington himself back in the 1790s. That building was opened in 1800, but it was burned down by the British during the War of 1812, and it had to be completely rebuilt.
    Well, to continue our tour, ladies and gentlemen, we are now traveling west on Madison Drive. Our next stop will be the Washington Monument--five hundred and fifty-five feet high and dedicated to George Washington, our first president. In the meantime, if you will look out of the window on the right, we’re just passing the National Gallery, which houses an extensive collection of European and American art from the 13 th to 20th centuries... By the way, this park-like area that we’re traveling along is called the Mall. It extends from the Capitol to the Washington Monument... Across the Mall, on the left, is the National Air and Space Museum, with exhibits on aviation history and the space age. If you have time, I highly recommend you to visit the Air and Space Museum for a fascinating look at the history of air and space travel... If you look straight ahead now, folks, you will see the Washington Monument. The Monument, an obelisk that stands five hundred and fifty-five feet high, was finished in 1884. We’ 11 be stopping there shortly, and those of you who wish will be able to take photographs from the observation level {ire hundred feet up. There is an elevator to take you there, and it’s safe.
    All right, everyone, here we are. We’ll be staying here approximately twenty minutes. For those of you who do take the elevator up to the top, if you look directly north, you’ll be able to get an excellent view of our next stop, the White House--the home of all our presidents since the second president, John Adams... Ok, remember to take all your personal belongings as you get off the bus. We’ll meet back here in twenty minutes...
Q. 15. Where will the passengers stop for twenty minutes?
Q. 16.What are the tourists able to do when they get to the Washington Monument?
Q. 17.Which of the following can NOT be learnt from the passage?
Q. 18.What is the tour route?