Questions & Answers about متى بنى المهندسون المجمع؟
How does المجمع (the complex) fit into this lesson's rules for nouns of place?
المجمع is derived from the Form II verb جمّع (to gather or assemble). For derived verbs (Forms II-X), the noun of place uses the exact same pattern as the passive participle. You take the present tense, replace the prefix with مـ (mu-), and give the second-to-last root letter a fatha (a). This creates مجمَّع (mujammaʿ), literally a "place of gathering," which we translate here as "complex."
I noticed المهندسون (engineers) also starts with a "mu" prefix. Is it related to the noun of place pattern?
It is closely related! مهندس (engineer) is the active participle of the Form II verb هندس (to engineer). While nouns of place (and passive participles) have a fatha (a) on the second-to-last root letter, active participles have a kasra (i) in that spot. So مجمَّع (mujammaʿ) is the place being gathered, and مهندِس (muhandis) is the person doing the engineering.
Why is the verb بنى (he built) in the singular form when the subject, المهندسون (the engineers), is plural?
In standard Arabic word order (Verb-Subject-Object), a verb that comes before an explicit subject is always conjugated in the singular. It only matches the subject's gender. Since المهندسون is masculine, the singular masculine verb بنى is used.
Why does the subject end in ـون (-ūn) rather than ـين (-īn)?