william shakespears is generally believed to have written all those plays himself

问题补充：having written all those plays himself 不是跟在to 后面..
偶的意思是为什么不可以是:william shakespears is generally believed having written all those plays himself
已经解释得很清楚了:
不是什么"having written all those plays himself 不是跟在to 后面.."的问题,
而是:
既然你用了.william shakespears is generally believed
后面就不能有:having written all those plays himself
不是跟不跟to后面 的问题.
be believed 后面,只能跟不定式和that 从句,这两种形式,不跟分词.
所以,你的说法是不对的.
william shakespears is generally believed to have written all those plays himself
be believed to do 被认为做了.
因为是完成时,所以用 to have written.
没有:be believed to doing 这种说法.
having written all those plays himself.
william shakespears is generally believed
这是主句
to have written all those plays himself
结果状语.