Commentary explaining the meaning of the ayahs. One passage often covers several ayahs, so neighbouring ayahs can show the same text.
English Al-Mukhtasar tafsir for Surah An-Naba — Ayah 20
وَسُيِّرَتِ ٱلۡجِبَالُ فَكَانَتۡ سَرَابًا ٢٠
And the mountains will be made to move until they become like dispersed dust particles; becoming like a mirage.