A、To restore the normal production of the oil wells. B、To estimate the losses caused by the fire. C、To remove the oil left in th

When Iraq troops blew up hundreds of Kuwaiti oil wells at the end of the Gulf War, Scientists feared environmental disaster. Would black powder in the smoke from the fires circle the globe and block out the sun?
    Many said, "No way, rain would wash the black power from the atmosphere". But in America, air sampling balloons have detected high concentrations of particles similar to those collected in Kuwait that didn’t catch fire. It has formed huge lakes in the Kuwaiti desert. They trap insects and birds, and poison a variety of other desert animals and plants.
    The only good news is that the oil lakes have not affected the underground water resources. So far, the oil has not been absorbed because of the hard sand just below the surface.
    Nothing, however, stops the oil from evaporating. The resulting poisonous gases are choking nearby residents. Officials are trying to organize a quick cleanup, but they are not sure how to do it. One possibility is to burn the oil. Get those black-powder detectors ready.
Questions 16 to 18 are based on the passage you have just heard.
16. What were the scientists worried about soon after the Gulf War?
17. What was the good news for scientists?
18. What are the officials trying to do at the moment?