Fred is a bus driver. He always drives the number 14 bus. Fred's bus goes 1the shopping mall on High Street to the park on Queen Street, then 2to the shopping mall. Fred3work at six o' clock every morning.4 bus leaves the shopping mall at ten past six. Fred is sometimes5 to work. When he is early, he sits in his bus and6the newspaper until it's time to go. Fred always stops for 7on the bus because he has to finish work at three o'clock in the afternoon. He doesn't go home by bus. He 8 ! He thinks it's really good for his health. Fred loved his 9 because he can meet different people every day. And he is very10. So the people who travel on Fred's bus like Fred very much.

某研究性学习小组做了以下实验：向溴水中加入足量乙醛溶液，观察到溴水褪色的现象．提出问题产生上述现象的原因是什么？

【提出猜想】

①溴水与乙醛发生取代反应．

② ____．

③ ____

【设计方案】

方案一：检验褪色后溶液的酸碱性．

方案二：测定反应前溴水中Br₂的物质的量和反应后Br^﹣离子的物质的量．

【实验探究】

取含0.005mol Br₂的溶液10mL，加入足量乙醛溶液使其褪色，再加入过量AgNO₃溶液，过滤、洗涤、干燥后称重固体质量为1.88g．

【解释与结论】

假设测得反应前溴水中Br₂的物质的量为a mol，若测得反应后n（Br^﹣）=0mol，则说明溴水与乙醛发生了 ____反应．若测得反应后n（Br^﹣）=amol，则说明溴水与乙醛发生了 ____反应．若测得反应后n（Br^﹣）=2amol，则说明溴水与乙醛发生了 ____反应．若已知CH₃COOAg易溶解于水，试通过计算判断溴水与乙醛发生反应的类型为 ____．理由是 ____其反应方程式为　 ____　．

反思与评价

方案一是否可行？ ____．理由是 ____

①小明看到同学生病了，主动送他回家，并帮他补习功课

②小李从来不和朋友争论，唯恐得罪朋友

③小芳看到自己的书籍被同学不小心弄坏了，气得再也不理他了 
④小冬看到自己的好朋友经常迟到，便提醒他按时到校