阅读下面一段文字，简要概括该实验得出的结论。（不超过25个字）

发展心理学研究中有一个经典的实验，称为“迟延满足”实验。实验者发给4岁被试儿童每人一块好吃的软糖，同时告诉孩子们：如果马上吃，只能吃一块；如果等20分钟后再吃，可以吃两块。有的孩子急不可待，把软糖马上吃掉了；而另一些孩子通过克制自己的欲望，迟延满足而吃到了两块软糖。研究人员进行了跟踪观察，发现那些吃到两块软糖的孩子，长大工作后，表现出较强的适应性。自信心和独立自主精神，事业上更容易获得成功；而那些经不住软糖诱惑只吃到一块软糖的孩子则往往屈服于压力而逃避挑战。

There are lots of rules at Selina's school.
She agrees with some1them. For example, they can't arrive2 , they can't  run in the hallways, and they can't eat in class. All3 rules are okay because they're reasonable(合情合理的).
But there are some rules Selina4agree with. For example, at her school they have to wear a uniform and they can't wear jeans. But she thinks jeans are5because they're comfortable. In school, they can't listen to music in art class. Selina doesn't agree with this rule. She thinks 6 music in art crass is okay.
Selina7 has to follow some rules at home. For example,8she wants towatch TV, she has to finish her homework first. And she can't go out with her friends 9school nights, that is, from Monday to Friday, she also has to clean her room10week. Luckily, she doesn't have to take out the trash（垃圾）. She hates it.

如果代数式x²+kx+49能分解成（x﹣7）²形式，那么k的值为（   ）

2011年，我国许多地方启动新一轮县乡基层人大代表的换届选举，城乡同比、结构优化、选民见面等成为本轮换届选举的新措施、新气象。这意味着  
①我国的选举制度越来越完善         ②我国在选举方式上有了创新 
③我国民主制度发生了根本性的变化   ④我国人民民主具有广泛性

持续79天违法“占领中环”的闹剧，于2014年12月15日告一段落，最终以失败告终。但已给香港造成诸多破坏，严重损害香港的社会秩序、经济发展和法治根基。“占中”闹剧给我们的警示是（   ）

①香港享有高度自治权  ②要坚持权利与义务相统一的原则  ③港人要依据宪法和香港基本法参与政治生活  ④香港保持原有的资本主义制度长期不变