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    Creating good habits can be as tough as breaking bad habits. From my experience, one of the most important factors ____ make forming a new habit hard is that a lot of willpower ____ (require), at least in the beginning, and that alone can prevent many people correctly developing their desired habits.

    Now instead of just using willpower and reminding ____ (you) to start the new habit each day, why don't you just link it to an existing one? I have done ____ experience. It started with just 20 pushups (俯卧撑), something easy. So before I showered each day, I would do the pushups. ____ a couple of days, I increased the amount just to make it a bit more challenging.

    Gradually, over the course of about 3 months, I'm now doing 100 pushups. And as the habit grew stronger, it got easier to do so ____ (natural). Now I know the habit is pretty much ingrained (根深蒂固), for I feel like something is missing ____ I don't do this before showering. I found it pretty easy ____ (create) this habit and not much willpower was involved.

    I think the key, apart from using an ____ (exist) habit, is to start out with something really easy. Once that starts becoming part of your ____ (day) routine, add on to it.

影响蒸发快慢的三个因素： ____ ____​ ____

材料一：三国和两晋时期，北方的匈奴、羯、氐、羌、鲜卑等少数民族开始内迁到黄河流域……各民族纷纷建立自己的政权……他们彼此征战，人民被屠杀，牛马被掠夺，城市化为废墟，田地大量荒芜，为躲避战乱，大批北方民众纷纷渡江南下，形成第三次南迁的浪潮。

材料二：魏晋以来，内迁的各族与当地的汉人错居杂处，开始过定居生活，他们不断向汉族人民学习，……民族隔阂不断消解，民族关系趋于和缓，到北朝后期。我国北方出现了各民族的大交融。

——节选自《人教版七年级教材》

材料三：三国鼎立时期，无论魏、蜀、吴都在局部地区实现了统一，这种局部统一较之东汉末年众多军阀割据混战的状况前进了一步，也为后来的全国统一准备了条件。各国都重视发展生产，整顿政治，增强国力，促进了局部地区经济的恢复和发展。魏、蜀、吴三国还重视处理与少数民族的关系，进一步促进了民族大融合。

2016年，我国全面实施一对夫妇可生育两个孩子的政策，这是我国进入21世纪以来，国家人口生育政策的又一次重大调整，其主要目的是（    ）