II. Choose A, B, C, D for each gap in the following sentences. 1. Air......................, together with littering, is causing many problems in our cities today. A. pollute B. pollution C. polluting D. polluted 2. The road in front of my office is always .................... when it rains heavily. A. to flood B. flooding C. flood D. flooded 3. Singapore is famous for its .................... and green trees. A. cleanliness B. cleanly C. cleaning D. clean 4. In some English speaking countries, turkey and pudding are ............... food at Christmas. A. national B. historical C. traditional D. possible 5. The USA has a population of 304 million, and it’s the third ............. country in the world. A. smallest B. largest C. narrowest D. highest 6. The roof of the building .......................... in a storm a few days ago. A. damaged B. was damaged C. has damaged D. has been damaged 7. A severe tropical ...................... is called a typhoon. A. drought B. rain C. flood D. storm 8. As soon as the floodwater ...................... down, people ........................ their houses. A. went - cleaned B. had gone – cleaned C. went - had cleaned D. had gone – had cleaned 9. If I were you, I ..................... do something to prevent him from littering. A. would B. did C. will D. do 10. Earth .................. by the gravity of the Sun and orbits around it. A. holds B. is held C. is holding D. held