user: Question: How many Arabic forms are there for the 1st. plur. perfect category?
Columns: ['Semitological abbreviation', 'Hebrew name', 'Arabic name', 'Morphological category', 'Hebrew Form', 'Arabic form', 'Approximate translation']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['G verb stem', 'Pa‘al (or Qal)', 'fa‘ala فَعَلَ (Stem I)', '3rd. masc. sing perfect', 'kataḇ כתב', 'kataba كتب', '"he wrote"']
SQL:

assistant: SELECT COUNT("Arabic form") FROM "Table" WHERE "Morphological category" = '1st. plur. perfect';