我认为不可能算出这道难题 。英语怎么说

Question

如题所述

Answer 1

I don't think it is possible to work out this question.
好像英语的习惯就是把否定放在前面。

Answer 2

I think it's impossible to solve this puzzle. or I don't think it's possible to solve this puzzle.

Answer 3

I don't think it is possible to work out such a difficult problem.

Answer 4

I don't think it is possible to work/figure out this difficult problem.