As it was mentioned in the previous lesson, to talk about actions that had to happen in the past, no matter they actually did happen or not, the past imperfective is used.
باید درس میخواندم.
نباید در کلاس میخوابیدیم.
I had to study.
1- We shouldn’t have slept in the class. (but we did.) 2- We were not to sleep in the class. (and thus we didn’t.)
Additionally, it is already known from earlier lessons that what has to be done is expressed using the present subjunctive tense.
باید امشب بروم.
نباید به دیگران بخندیم.
I should go tonight.
We should not laugh at others.
However, using an impersonal construction is another common way to suggest necessity for cases when no specific subject is intended. That is by using the third person singular form of the verb in the past simple tense.
باید به فقیران کمک کرد.
نباید ساکت ماند.
One should go.
One should help the poor.
One should not remain silent.
It was seen in the present subjunctive lesson that the common way for expressing ability is to use the verb in present subjunctive tense preceded by a verb of the infinitive “توانستن” (to be able).
نتوانستیم با هم زندگی کنیم.
Can we go?
I can’t help saying [it].
I couldn’t meet him/her.
We couldn’t live with each other.
Here, both of the verbs (“توانستن” and the main verb) are being conjugated with regard to the subject. Alternatively (and with a slight change in meaning), it is possible to use the third person singular form of the verb “شدن” instead of the conjugated verb from the infinitive “توانستن”.
نمیشد با هم زندگی کنیم.
May we go?
It’s not possible for me not to say [it].
It wasn’t possible for me to see him/her.
It wasn’t possible (continuous) that we live with each other.
Again, there are times that no specific subject is intended in the sentence. In such a situation, the main verb comes in third person singular form and in past tense.
اینجا نمیشود حرف زد.
با این اختراع میشود دنیا را نجات داد.
میشود دعوا نکرد.
از پشتِ در میشد صدایشان را شنید.
میشُد دروغ گفت، ولی من دروغ نگفتم.
It is possible to go.
Here, it is not possible to talk.
With this invention one can save the world.
It is possible to avoid quarreling.
From behind the door, it was possible to hear their voice.
It was possible to lie, but I didn’t lie.
The Impersonal Pronoun
The Persian impersonal pronoun “آدم” (literally meaning “human”) is used in place of any possible person, similar to the English pronoun “one” and the French pronoun “on”. Using this pronoun is very common in spoken language.
توی این هوا، آدم مریض میشود.
آدم نمیفهمد او چه میگوید.
دلِ آدم برایش میسوخت.
این مردم آدم را خسته میکنند.
One gets sick in this weather.
One doesn’t understand what he says.
One felt sorry for (literally: One’s heart burnt for) him/her.