A predicate is one of the two main constituents of a sentence or clause, modifying the subject and including the verb, objects, or phrases governed by the verb.
When a noun is part of the predicate, and it is modified by an attributive adjective, it takes the indefinite enclitic ی, whether it is singular or plural:
.علی پسر خوبی است
ali pesar-e xubi ast
“Ali is a good boy.”
.آن فیلم، فیلم زیبایی بود
ān film, film-e zibā-yi bud
“That movie was a beautiful one.”
.دکتر اردشیری پزشک حاذقی است
doctor ardeširi pezešk-e hāzeqi ast
“Dr. Ardeshiri is a skillful physician.”
.اینها کتابهای مفیدی است
in hā ketāb hā-ye mofidi ast
“These are (some) useful books.”
.آنها مردان بزرگی بودند
ān hā mardān-e bozorgi budand
“They were (some) great men.”
NOTE: Remember that است ast ‘is’ may be contracted into a preceding long vowel. Therefore, a variation of some of the above sentences would be: علی پسر خوبیست , دکتر اردشیری پزشک حاذقیست , and اینها کتابهای مفیدیست .
Nouns can be repeated for emphasis, as in the French:
.اینها گلهایی خوشبوست
in hā, gol hāyi xošbust
“These flowers smell nice.”
.آن کتاب، کتابی عالیست
ān ketāb, ketābi ālist
“That book is a magnificent book.”
Since the indefinite enclitic ی is mobile, in the above sentences it may be placed at the end of the nouns or the adjectives:
.علی پسری خوب است
ali pesar-i xub ast
“Ali is a good boy.”
.آن فیلم، فیلمی زیبا بود
ān film, filmi zibā bud
“That movie was a beautiful one.”
.دکتر اردشیری پزشکی حاذق است
doctor ardeširi pezeški hāzeq ast
“Dr. Ardeshiri is a skillful physician.”
.اینها کتابهایی مفید است
in hā ketāb hā-yi mofid ast
“These are (some) useful books.”
.آنها مردانی بزرگ بودند
ān hā mardāni bozorg budand
“They were (some) great men.”
There is no definite article (“the”) in Persian. In addition, the indefinite article (“a”) is not used with a generic noun (see example 2 below). Therefore a Persian noun is either absolute or non-specific. It is only within the syntax of a sentence that the noun is defined as being specific or non-specific:
.مرد را دیدم
mard rā didam
“I saw the man.”
.من دانشجو هستم
man dānešju hastam
“I am a student.”
The demonstratives این in ‘this’ and آن ān ‘that’ make a noun specific/definite:
.این مرد را دیدم
in mard rā didam
“I saw that (particular) man.”
.آن کتاب خوب است
ān ketāb xub ast
“That book is good.”
In its absolute state, a noun is normally generic (which is usually pluralized in English) and singular. Compare and contrast between Persian and English in the following examples: