Choose the correct answers.(选择正确的选项) 1. Every possible means _______ to prevent the air pollution, but the sky is still not clear. A.is used B.are used C.has been used D. have been used 2. No one in the department but Tom and I __ that the director is going to resign. A.knows B.know C.have known D.am to know 3. Traditional folk arts of Tianjin like paper cutting _________ at the culture show of the 2010 Shanghai World Expo. A. were exhibiting B. was exhibiting C.were being exhibited D. was being exhibited 4. Walmart, which is one of the largest American supermarket chains, ______ some of its store open 24 hours on Mondays through Saturdays. A. keeps B.keep C.have kept D.had kept 5. He is the only one of the students who _____ a winner of scholarship for three years. A.is B.are C.have been D.has been 6. Listening to loud music at rock concerts _________ caused hearing loss in some teenagers. A.is B.are C.has D.have 7. Professor Smith, along with his assistants, _______ on the project day and night to meet the deadline. A.work B.working C.is working D.are working 8. Either you or one of your students ______ to attend the meeting that is due tomorrow. A.are B.is C.have D.be 9. A survey of the opinions of experts _______ that three hours of outdoor exercise a week _______ good for one’s health. A.show; are B.shows; is C.show; is D.shows; are 10. Though there only a small quantity of food and water left, they managed to arrive at the destination, safe and sound. A. is B. was C. were D. are