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ha*t is second nature. 习惯成自然。
custom makes all things easy. 若照习惯办，万事皆不难。
custom is a second nature. 习惯是第二天性。
a bad custom is like a good cake, better broken than kept. 坏习惯像鲜馅饼，分食要比保存好。
practice makes perfect. 熟能生巧。
don't leave today's work for tomorrow. 当日事，当日毕。