这个问题很难解决。

Zhège wèntí hěn nán jiějué.

This problem is hard to solve.

没有问题是解决不了的。

Méiyǒu wèntí shì jiějué bùliǎo de.

No problem is unsolvable.

只要一起努力，我们一定能解决这个难题。

Zhǐyào yìqǐ nǔlì, wǒmen yídìng néng jiějué zhège nántí.

As long as we work hard together, we can definitely solve this difficult problem.