Question

i find it difficult to achieve this goal中的it是作什么成分。形式宾语吗？

i find it is difficult to achieve.这句话是对的吗.

Answer 1

没错，是形式宾语
I find it is difficult to achieve 也对，但这里便是一句宾语从句，I find （that）it is……that 被省略了

Answer 2

i find it is difficult to achieve:错的······
i：主语
find：谓语
it：宾语
difficult to achieve this goal：宾补

Answer 3

i find this goal is too difficult to be achieved
i find it is difficult to be achieved