单项选择题 DECIBEL: SOUND::（）

单项选择题 Though managers of commercial shellfish beds in many countries monitor the presence of pollutants using mice, this method is ethically（）and too expensive for many developing countries, small operations or amateur fishermen.

单项选择题 In spite of（）among a few scientists, and years of（）discussion, the claim that earthquakes can be predicted with great precision prevails.