那一瞬间，我突然明白了老师的话。

Nà yí shùnjiān, wǒ tūrán míngbai le lǎoshī de huà.

In that instant, I suddenly understood what the teacher meant.

城市的变化仿佛在一瞬间完成，让人难以相信。

Chéngshì de biànhuà fǎngfú zài yí shùnjiān wánchéng, ràng rén nányǐ xiāngxìn.

The changes in the city seemed to be completed in an instant, making it hard to believe.