题干

 (1)某电视节目中有个“土壤兄弟”,提倡人们不要随地乱丢废旧电池,你认为这样做的理由是 ____,还有个“空气兄弟”建议我们少开私家车,多乘坐公交车、骑自行车或步行,你认为这样做的理由是 ____

(2)实验室有两瓶标签破损的无色溶液,推知它们只能是碳酸钠溶液和硝酸钡溶液.某校兴趣小组的同学设计实验区分它们,请你参与实验,选择下列试剂进行区分,并回答有关问题.试剂:

①pH试纸     ②KOH溶液    ③Ca(OH)2溶液    ④稀硫酸⑤Na2SO4溶液


所选试剂(填序号,每种方法只选择一种)

实验现象及结论

方法一

 ____

 ____

方法二

 ____

 ____

上一题 下一题 0.0难度 选择题 更新时间:2012-06-21 10:43:34

答案(点此获取答案解析)

\u9632\u6b62\u5e9f\u65e7\u7535\u6c60\u4e2d\u7684\u91cd\u91d1\u5c5e\u7b49\u6cc4\u6f0f\u800c\u9020\u6210\u571f\u58e4\u6c61\u67d3,\u51cf\u5c11\u7531\u4e8e\u6c7d\u8f66\u5c3e\u6c14\u7684\u76f4\u63a5\u6392\u653e\u800c\u9020\u6210\u7684\u5927\u6c14\u6c61\u67

同类题1

阅读理解

    In Los Angeles, a waiter served a group of teens. The waiter remembered his experience as a young high school prudent. So he made sure the teens had a pleasant experience at the restaurant. The waiter made sure of it.

    After serving all the teens doing a great job, he was left a tip(小费),only $3.28. That was hardly enough to buy a drink at Roebucks.

    The waiter went home. And he felt hatred for the students who did not know the value of hard work. They looked down on people like him. Or so he thought.

    After several days, the waiter forgot about it. His life went on as usual. But ten days later, he received a letter from the teens.

    “About a week and a half ago, on October 7, my three friends and I came to eat at this restaurant as our own homecoming celebration. It was an exciting experience for us to be here alone, and it was all new to us. And you were the best waiter we could ask for. You were kind, helpful, and didn't treat us like babies! So I want to say thank you for making our 'groan-up' experience so amazing and fun.

    “I would also like to say sorry on behalf of(代表) my group. Since we were new to all of this, reasonable(合乎情理),but we had completely forgotten(and didn't know, to be honest) what a tip even was, let alone how much to give. So we emptied our pockets, and all our money added up to $3.28.

    “Having no idea of how small this really was, we left. Later, we realized our mistake and felt terrible. We knew we had to make it right.

    “So together with this letter, you will find the correct 18% tip + extra for simply being amazing. Thank you for your help and patience and also thank you for making our night fun. Thank you!”