Ex. 2 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