—I need some fresh air, so I am going out for a walk.—________.
17..In the United States, bus travel doesn't cost much as train travel, ? 18.
19..Someone is at the door, who is_________? 20.
21.—It is raining cats and dogs. 22. — .. 23.
19.—My home is in that tall building over there. — ?
20. _________raining hard for 3 hours without stopping. 21.