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.
اِسْتَطْوَعَ → اِسْتَطَاعَ Past: heاِسْتَطْوَعَتْ → اِسْتَطَاعَتْ Past: sheاِسْتَطْوَعْتَ → اِسْتَطَعْتَ Past: you (m.)اِسْتَطْوَعْتُ → اِسْتَطَعْتُ Past: I