يَوْمَ تُبْلَى ٱلسَّرَآئِرُ
Sentence structure
يَوْمَ is an accusative time adverb. Its following clause has passive تُبْلَى and nominative ٱلسَّرَآئِرُ as the deputy subject.
Ayah summary
On the Day of Resurrection, the secrets of hearts and hidden deeds will be exposed and examined.
يَوْمَ — (The) Day
Grammar: An accusative time adverb.
تُبْلَى — will be tested
Grammar: A third-person feminine-singular passive indicative imperfect; its clause is annexed to يَوْمَ.
ٱلسَّرَآئِرُ — the secrets
Grammar: ٱل is the definite article; سَّرَآئِرُ is the feminine-plural nominative deputy subject of تُبْلَى.