演奏小提琴似乎是简单的事；然而这需要多么长期和艰苦的练习呀！
It may seem a simple affair to play upon a violin; yet what a long and laborious practice it requires!
在4月7日出版的Nature杂志中发表这项经过长期和艰苦的实验所到的结果。
The work, the result of years-long and laborious experimentation, is published April 7 in the journal Nature.
麦凯恩在这场选战中进行了长期和艰苦的努力，他为这个他所爱的国家战斗了更长的时间，作出了更艰苦的努力。
Sen. McCain fought long and hard in this campaign. And he's fought even longer and harder for the country that he loves.
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