Common mistakes
The middle radical is و or ي. It stretches into a long vowel: قَالَ: and shortens before a consonant ending and in the jussive: قُلْتُ, لَمْ يَقُلْ.
سَيَرَ → سَارَ Past: heسَيَرَتْ → سَارَتْ Past: sheسَيَرْتَ → سِرْتَ Past: you (m.)سَيَرْتُ → سِرْتُ Past: I