请教NN们一个英语句子Onlysevenpeoplethiscenturyhavebeenkilledbythegreatwhiteshark,theman-eaterofthemovies—fewerthanhavebeenkilledbybeestings.请教NN们,onlyseven...thegreatshark作主句,theman-eaterofth

　　请教NN们一个英语句子

　　Onlysevenpeoplethiscenturyhavebeenkilledbythegreatwhiteshark,theman-eaterofthemovies—fewerthanhavebeenkilledbybeestings.

　　请教NN们,onlyseven...thegreatshark作主句,theman-eaterofthemovies作shark的同位语,那么后面的fewerthan...这里在句中作什么结构呢?

　　还有这个破折号在此作何理解呢?若不用破折号又该怎么表达这里呢?

　　谢谢