翻译：“senna was arguably the greatest racing driver of all tim

arguably可以论证地,论证上；the greatest最高级形式；of all time有史以来
把整句话划分开来结构就清楚了如：
senna was [arguably] (the greatest)( racing) driver (of all time)
先不管修饰词整句话就是“senna was driver 塞纳是车手”
再加形容词来翻译“senna was the greatest racing driver of all time 塞纳是有史以来最伟大的赛车手”最后再加上副词的修饰.所以整句话的意思是：“事实证明塞纳是有史以来最伟大的赛车手”.
说明：你可能会问既然是“有史以来”为什么还要用"was",那是因为塞纳已经过世了!