空气·苍蝇·暖气包王力德俗话说：“有一利必有一弊”。比如打开窗户流通空气，苍蝇要飞进来；如果完全关严，苍蝇和新鲜空气就都进不来了。在这里“弊”与“利”是成正比的，新鲜空气和苍蝇是密不可分的。按照常规思维方式，似乎只能权衡利弊，在窗户打开的“度”上做适... Air, flies, and heating packs Wang Lide said: “There is a disadvantage for one advantage.” For example, when you open a window to circulate air, the fly will fly in; if it is completely closed, neither flies nor fresh air will enter. Here, “disadvantages” and “profits” are proportional, and fresh air and flies are inseparable. In accordance with conventional thinking, it seems that only the pros and cons can be weighed, and the “degree” of window opening is appropriate...