题目

某兴趣小组根据实验室提供的仪器和药品进行了气体的制备实验． （1）甲同学选用如A图所示的装置制取氧气． ①写出仪器a的名称： ． ②甲同学应选取的试剂是 、 （填化学式） ③实验前，甲同学先向仪器a中加入水，然后将导管放人水槽中，并打开仪器A的活塞，观察导管口是否有连续的气泡出现．该实验操作的目的是 ． （2）乙同学称取一定质量KMnO4放在大试管中，如图B加热，将温度控制在250℃加热制取O2，该反应的符号表达式为 ． 实验结束The goal of earthquake prediction is to give early enough warning. The U.S. Geological Survey conducts and supports research on the likelihood of future earthquakes. Scientists estimate earthquake probabilities in two ways: by studying the history of large earthquakes in a special area and the rate at which strain（拉力）accumulates（积累）in the rock. Scientists study the past frequency of large earthquakes in order to determine the future likelihood of similar large shocks. For example scientists researched the large earthquakes in the San Francisco Bay region during the 75 years between 1836 and 1911. For the next 68 years, no earthquakes of magnitude (震级) 6 or large occurred in the region. Beginning with a magnitude 6 shock in 1979, the earthquakes in the region increased dramatically; between 1979 and 1989, there were four magnitude 6 or greater earthquakes, including a magnitude 7.1 earthquake. So scientists estimated that the probability of a magnitude 6.8 or larger earthquake occurring during the next 30 years in the region is about 67 percent. Another way to predict earthquakes is to study how fast strain accumulates. When plate movements build the strain in rocks to a critical level, like pulling a rubber band too tight, the rocks will suddenly break and slip to a new position. Scientists measure how much strain accumulates along a fault (断层) each year, how much time has passed since the last earthquake, and how much strain was released in the last earthquake. This information is used to calculate the time required for the accumulating strain to build to the level that results in an earthquake. This simple model is so complicated that such detailed information about faults is rare. In the United States, only the San Andreas Fault System has adequate records for using this prediction method. Scientific understanding of earthquakes is of vital importance to the Nation. As the population increases, expanding urban development and construction encroach (侵蚀) upon areas susceptible(易受影响的) to earthquakes. With a greater understanding of the causes and effects of earthquakes, we may be able to reduce damage and loss of life from this destruction1.What does the passage mainly talk about?A.What an earthquake is likeB.How to predict earthquakesC.Where earthquakes often happenD.When a fault is formed2.That scientists study the history of large earthquakes in certain areas is to ultimately______.A.do research on the past frequency of large earthquakesB.estimate the magnitude of similar earthquakesC.forecast the possibilities of similar earthquakesD.judge the specific location of future earthquakes3.Which is TRUE according to the passage?A.There were four magnitude 6 earthquakes in the San Francisco Bay region between1979 and1989B.The accumulating strain of the fault to a certain level results in the earthquakeC.About 68 years after 1911, no earthquakes occurred in the San Francisco Bay regionD.The fast increasing population on the earth is the main cause of the earthquake4.What is the critical factor of forming a fault?A.The material of rocksB.The existing time span of the rocksC.The plate movements around the rocksD.The amount of strain released in the last earthquake5.According to the passage, we can know that the San Andreas Fault System______.A.has a greater understanding of the causes and effects of earthquakesB.stores much more information about the history of large earthquakesC.offers the potential for doing research on the faults where strain accumulatesD.illustrates specifically how rocks along a fault are formed