The book's exercises include يَجْتَنِبُ، يَكْتُبُ، يَسْمَعُ، يَعْلَمُ and يَمْنَعُ. Their stem vowels should not be forced into one universal pattern; each verb follows its own morphological form.
Word / formMeaning / explanation
يَجْتَنِبُhe avoids; Form VIII (iftʿāl).
يَكْتُبُhe writes; basic root k-t-b.
يَسْمَعُhe hears; basic root s-m-ʿ.
يَعْلَمُhe knows; basic root ʿ-l-m.
يَمْنَعُhe prevents; basic root m-n-ʿ.
All five begin with يَ as active third-person masculine singular, yet their internal vowels identify different conjugational patterns.