This effect, which researchers call “desirable difficulty,” is evident in daily life.
研究者把这个效果称为“值得经历的困难”，这一点在日常生活中也表现得很明显。
Oh! My dear, we cannot begin too early; you are not aware of the difficulty of procuring exactly the desirable thing.
哦！亲爱的，越早打听越好。你不知道找一个称心的人家有多难哪。
Only after a good combination of both the difficulty and the aesthetic feeling can take it a desirable artistic effect.
体操中的难度与美感既是矛盾的，又是统一的，难度与美感只有交融在一起，才能产生高水平的艺术效果。
Only after a good combination of both the difficulty and the beauty can it take a desirable artistic effect.
难度与美只有交融在一起，才能产生高水平的艺术效果。
Only after a good combination of both the difficulty and the beauty can it take a desirable artistic effect.
难度与美只有交融在一起，才能产生高水平的艺术效果。
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