Questions & Answers about امروز زنان و دختران خوشحال هستند.
How are the plural words for "women" and "girls" formed in this sentence?
Both زن (woman) and دختر (girl) refer to people, so they take the animate plural suffix ـان (-ân). Adding it makes them زنان (women) and دختران (girls).
The lesson mentions ـگان (-gân) and ـیان (-yân) for plurals. Why don't we use those here?
You only need those variations when a word ends in a vowel. Because the base words زن (zan) and دختر (dokhtar) end in consonants ('n' and 'r'), you just add the standard ـان (-ân) directly to the end of the word.
Why doesn't the adjective خوشحال (happy) get a plural ending to match the women and girls?
In Farsi, adjectives never change to become plural. Even though the subjects are plural, the adjective خوشحال stays in its normal, base form. You do not need to make adjectives "agree" with the noun like you do in some other languages.
Why is امروز (today) at the very beginning of the sentence?
Farsi is quite flexible with time words, but placing a time word like امروز at the very beginning of a sentence is the most common and natural way to set the scene. Remember that while time words can move around, the verb هستند (are) must always go at the very end!