①由上述信息可知：压力变阻器R所受压力越大时，通过它的电流越____，其阻值越____．

②若将显示质量大小的仪表V并联在压力变阻器R两端，使用该电子秤时，会观察到的现象是____，理由是____．

若分式$\frac{x^2-2x-3}{x+1}$的值为0，则x的值为（　　）

煤是重要的能源，也是化工生产的重要原料．

（1）煤燃烧产生的废气直接排放到空气中，可能导致的环境污染问题是 ____．

（2）下图是对煤燃烧产生的废气进行常温脱硫处理的流程示意图．

①废气脱硫过程中，主要反应的化学方程式为 ____ ____

②在煤中直接添加一种物质，可有效减少煤燃烧产生的SO₂，该物质是 ____

③石膏在工业生产中的用途是 ____（写出一种用途即可）．

（3）煤经过 ____（填加工方法）可以得到炉煤气、煤焦油和焦炭．煤焦油经过 ____（填加工方法）可得到芳香族化合物．煤也可以用氢化法转化成燃油，氢化法的本质是 ____

阅读下面短文，然后根据短文内容回答问题
     Stephen Hawking was born in Oxford（牛津），England on the eighth of January, 1942. He went to school in ST Albans-a small city near London. After leaving school, Mr. Hawking went to Oxford University where he studied physics, then he went to Cambridge University（剑桥大学）．
      When he was 29 years old, Mr. Hawking got a bad illness. He couldn't speak or一 move without the help of a machine（机器）．Doctors said they, had no way to help him. He would die before he was 23. At first, Mr. Hawking became very sad. After a while, though, he began to see his life in a different way. He worked hard and later became a very famous professor（教授）．Today he still works at Cambridge University as a professor.