高压设备的划分标准是()。

Which of the following titles is most appropriate to the text?A．The Failed Search for an Earthquake Prediction SystemB．The Merits of Trying to Predict EarthquakesC．The Debate over Earthquake Prediction SystemsD．The Drawbacks of Earthquake Prediction Systems 点击查看答案

Which of the following best sums up activities within an ecosystem?A．Predator-prey relationships.B．Interactions among all members.C．Human-animal interactions.D．Human relationship with the environment. 点击查看答案