And if they were to see a fragment from the sky falling, they would say, "[It is merely] clouds heaped up."
The Saheeh International Quran Translation
وَإِن يَرَوْا۟ كِسْفًا مِّنَ ٱلسَّمَآءِ سَاقِطًا يَقُولُوا۟ سَحَابٌ مَّرْكُومٌAnd if they were to see a fragment from the sky falling, they would say, "[It is merely] clouds heaped up."