题目

下列图像分别与选项中的操作相对应，其中合理的是 A． A B． B C． C D． D 答案：B【解析】 A、向一定量的氢氧化钠溶液中加水时，溶液的碱性变弱，但一直呈碱性， pH始终大于 7，错误； B、碳酸氢钠和氯化氢的质量比为： 84:44，碳酸钠和二氧化碳的质量比为： 106:44，一定质量的碳酸氢钠比同质量的碳酸钠生成二氧化碳更多，正确 ； C、镁的活动性比铁强，所以镁先反应完， 阅读理解 　　When middle-aged Alex gave up his job and made up his mind to become a self-employed writer, no one could tell surely whether he would succeed or not．He found a cold storage room in a building, set up a used typewriter and settled down to work． 　　After a year or so, however, Alex began to doubt himself．He found it was difficult to earn his living by selling what he wrote．But Alex determined to put his dream to the test－even though it meant living with uncertainty and fear of failure．This is the shadowland(虚幻世界)of hope, and anyone with a dream must learn to live there． 　　One day Alex got a call, "We need an assistant, and we're paying ＄ 6,000 a year．" ＄ 6,000 was real money in 1960．It would enable Alex to get a nice apartment, a used car and more．Besides, he could write in his spare time．As the dollars were dancing in Alex's head, something cleared his senses．He had dreamed of being a fulltime writer．"Thanks, but no," Alex said firmly and swiftly, "．" 　　After Alex got off the phone, he pulled out everything he had：two cans of vegetables and 18 cents．Alex put the cans and cents into a paper bag, saying to himself," There's everything you've made of yourself so far．I'm not sure I ever felt so low．" 　　Finally his work was published in 1970．Instantly he had the kind of fame and success that few writers ever experience．The shadows had turned into focus of attention． 　　Then one day, Alex found a box filled with things he had owned years before．Inside was a paper bag with two cans and 18 cents．Suddenly he pictured himself working in that cold storage room．It reminds Alex, and anyone with a dream, of the courage and persistence(坚毅)it takes to stay the course(坚持到底)in the shadowland． (1) Why did Alex give up his job? [　　] A． Because he didn't like the working conditions． B． Because he couldn't earn enough to make a living． C． Because he felt he had no potential in his job． D． Because he wanted to be a full-time writer． (2) What did Alex express when he answered the call? [　　] A． He refused the job offer． B． He was willing to give them a hand． C． He expected them to pay him more money． D． He would write in his spare time． (3) What kind of person is Alex? [　　] A． Determined． B． Modest． C． Shy． D． Brave． (4) Which of the following can be the best title of the passage? [　　] A． Look before you leap． B． Two heads are better, than one． C． Hold on to your dream, and it will come true． D． A bird in hand is worth two in the bush．