I cannot hear the professor clearly as there is too much noise I am sitting.
A. before
B. until
C. unless
D. where
网友回答
A. before
B. until
C. unless
(答案→)D. where
解析：before在……之前，until直到 unless除非 where在……地方，句意为，我听不清那个教授在讲什么，因为在我现在坐的地方噪音太大。故选择D项。
【考点定位】考察连词的用法。