【题目】Pollution is damaging the environment, and the situation is particularly ________ in big cities.
A. abstract B. stable
C. rigid D. acute
在线课程【答案】D
【解析】考查动词词义辨析。句意：污染正在破坏环境，这种情况在大城市里特别严重。A. abstract抽象的；B. stable稳定的；C. rigid严格的；D. acute严重的。根据语境，故选D。