lucylu

1.本句主语是the QUET，前面是他的同位语，谓语是had,所以and it is believed to have been是完全正确的。
2.and it is believed to have been中的it is 是不能省略的。
3.句中用了the world has ever seen，所以believed to的结构用了完成式。


[em12]