The past tense

The past tense adds endings to the root: كتب (he wrote), كتبت (she wrote, or I wrote, or you wrote), كتبنا (we wrote), كتبوا (they wrote). Without vowel marks, كتبت can mean several persons; the context decides.

The plural they ending, وا, takes a silent alif after the waw: ذهبوا, كتبوا. It is written but never pronounced, and nouns never take it: معلمو المدرسة.

Negate the past with لم plus the present: لم يكتب (he did not write), or with ما plus the past: ما كتب.