Mark the letter A, B, C or D to indicate the sentence that best combines each pair of sentences in the following questions 27. Electric car causes no air pollution, but they still cause traffic jams. A. Although electric car causes no air pollution, but they still cause traffic jams. B. Although electric car causes no air pollution, they still cause traffic jams. C. Electric car causes no air pollution, however they still cause traffic jams.D. In spite of electric car causes no air pollution, they still cause traffic jams. 28. "Is your son interested in sciences?", said the teacher to Mr. Smith. A. The teacher wanted to know if Mr. Smith's son is interested in sciences. B. The teacher wanted to know if Mr. Smith's son did interested in sciences. C. The teacher asked Mr. Smith whether his son was interested in sciences. D. The teacher asked if Mr. Smith's son was interested in sciences. 29. The government should provide contemporary shelters for the earthquake victims. A. Contemporary shelters should be provided by the government for the earthquake victims. B. Contemporary shelters are provided for the earthquake victims by the government. C. Contemporary shelters should be provided for the earthquake victims by the government. D. Contemporary shelters will be provided for the earthquake victims by the government. 30. The first experiment is unsuccessful, so we need to do another one. A. If the first experiment is successful, we don't need to do another one. B. Unless the first experiment was not successful, we don't need to do another one. C. Unless the first experiment was successful, we wouldn't need to do another one. D. Unless the first experiment was successful, we would need to do another one. 31. The reporter wanted to know why I hadn't taken a picture when I saw an UFO. A. The reporter asked, "Why had you not taken a picture when you see an UFO?" B. "Why didn't you take a picture when you saw an UFO?", asked the reporter. C. "Why didn't you take a picture when you see an UFO?", asked the reporter. D. "Why haven't you taken a picture when you saw an UFO?", asked the reporter. 32. Man is likely to live on Mars in the future. A. Man will probably not live on Mars in the future. B. Man will probably live on Mars in the future. C. Living on Mars is unlikely. D. Living on Mars will be likely to be wrong.