1.they were cleaning the room when I arrived 2.they must dry the beans in the sun 3.the foreman is showing the students around the factory 4.A Chinese official made paper from wood pulp in the year 105 5.people say the computer is one of the most important inventors 6.we haven't finished our homework yet 7.they will make the next meeting in Chicago 8.when did Lewis waterman invent the fountain pen 9.somebody clean the room everyday 10.john will collect me at the airport 11.your teacher must sign this form 12. will you invite her to your birtday party 13.we can't wear jeans at work