Chokwe Selassie, aged 13, is working hard to help drivers avoid potholes(坑洼). The eighth-grader was inspired to kick off his creation on a recent morning, when his mother was driving him to school. Their car was damaged as it went over a huge pothole in the middle of the street in their hometown of Jackson, Mississippi. He decided to do something about the pothole problem in his city. His solution: an app that warns drivers when there is a pothole ahead.

    Chokwe developed the app with his friends Rodriguez Ratliff and Emmanuel Brooks. When the app detects a pothole, it is highlighted in red. And if you get close to the pothole, your phone will warn you. Drivers can also use the app to report any potholes they meet, and to look for other routes they can take to avoid roads that have them.

    The app relies on current available information about the streets of Jackson. It works by using the city's 311 call system, and uses information already stored in a database. Through the call system, citizens dial 311 to report non-emergency problems, which include potholes. Chokwe and his friends determined that focusing on the 10 busiest streets in Jackson would give them a large enough sample size to test the prototype（原型）.

    Although the app isn't yet available for sale,Chokwe is already looking for ways to improve it. The prototype remains limited to 10 streets in Jackson, but he hopes to add more, so that it includes every street in the city. And then he wants to go even farther until it's nationwide.

    词在发展的初期，普遍被视为“小道”。不过，起源于民间的文体，到了文人手中，往往被赋予更深的意义，因而几乎在词得到北宋文人比较普遍喜爱的同时，词坛就出现了尊体①之说。这一学说大致是在相反相成的两个层面展开的。

    北宋前期，《花间》、南唐词风盛行，学之者多追求风格细腻柔婉，至柳永则趋于平俗浮靡，于是有苏轼对传统词风的改革。苏轼改革词风的方式是“以诗为词”，主要表现为对题材内容的拓展，对格调意蕴的重视等。这在主要以倚红偎翠为基本内容的传统中，显得非常另类，所以当时经常得到讽刺性的评价。

    值得提出的是，苏轼的这一类创作有着非常鲜明的自觉意识。这表现在，首先，他要突破传统，自成一家。其次，他在文学创作上一贯具有争胜心态。对词坛上某些冲破《花间》、南唐词风的努力，他应该是曾经注意的。以我们对苏轼个性的了解，他肯定要在这方面继续力争超越前人。所以，苏轼实际上是在几个方面争胜，既有和传统词风的争，也有和体现士大夫意识的新兴词风的争，前者是破，后者则是进一步立。

    就在苏轼提出词“自是一家”不久，李清照又提出了词“别是一家”的说法，同样进行了“尊体”的探讨。不过，和苏轼不同，李清照主要是从词的体性入手的。在其著名的《词论》中，这位女词人对北宋词坛作了全面梳理，在对所谓“俗词”大加声讨的同时，主要批评了忽视词的音乐性的做法。因为词自产生以来，本身就是一种音乐文学，到了李清照的时代，仍然主要是音乐文学。偏离了这一传统，或者使得这一传统变味，显然不能为词坛的多数人接受。

    尽管苏轼和李清照的词论彼此带有一定的否定性，但不可否认，二者都有尊体的动机。前者是从意义的层面上，要把词向传统诗文的表达功能靠拢，从而否定“小道”之说；后者则从词的本来意义上，强调艺术的精工，从而保证这一文体的特殊性。看似相反，实则相成。

    苏轼和李清照的尊体论，实际上从两个方面划出了中国词史的轨迹，因而在后世不断得到回应。

【注】①尊体：指词这种体裁被词作家所推崇，不再被视为“小道”。

实验室用加热高锰酸钾来制取氧气，有如下操作步骤：①加热；②检查装置的气密性；③装药品；④用排水法收集氧气；⑤从水槽中取出导管；⑥熄灭酒精灯；⑦连接装置。其操作顺序正确的是（   ）

有人认为：“成功的关键在于发挥优点，而不是克服缺点。”

运用矛盾基本属性的指示对此加以辨析。