He was the first pianist in the 70-year history of the competition to win the prize
问题描述：
He was the first pianist in the 70-year history of the competition to win the prize
答
没错
the + 序数词+ 名词+ 不定式
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答
对的，没有语法错误。
个人更倾向于：
He was the first pianist in the 70-year history of the competition who had won the prize.
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满意请采纳，谢谢o(∩_∩)o
答
没有问题。。。
改成这样比较顺He was the first pianist to win the prize in the 70-year history of the competition .
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答
the 70-year，没怎么见过这种写法
答
对的.
He（主） was（系动词） the first pianist （表语）in the 70-year history of the competition （表语的后置定语）,to win the prize（补语）.
意义：在该项比赛的70年历史上,他是第一个获得这一奖项的钢琴家.
）