14. Most people admit that they contribute to global warming. A. be partly responsible for B. disapprove C. neglect D. cause 15. We must admit that people are heavily polluting the environment. A. decline B. rebut C. deny D. accept 16. In the polluted environment, infectious diseases can be passed easily from one person to another. A. fatal B. safe C. contagious D. immune 17. Global warming has severe impact on water supplies. A. very good B. very bad C. normal D. long-lasting 18. Global warming occurs when the greenhouse gases in the atmosphere trap the heat from the sun. A. catch B. discharge C. dispose D. release