请问这道英语语法题There ought to be less anxiety over the perceived r

主要从意思上区分.
在当今社会,对于检察到患癌症的危险,比起实际存在的,本不应该有那么多的焦虑.
就是说,把句子分一下,就好做了.
弄清比较对像,因为than两边,结构对等.
over the perceived risk of getting cancer ,
对于检察到患癌症的危险,
There is much anxiety exists in the public today.
在当今社会,存在很多焦虑
but it ought to be less .
但,这种情况（There is much anxiety exists 这是个事实,用现在时,）本不应该有那么多.
省略相同成分,就只剩下exists.