Breakdown of Вы должны требовать, чтобы официальная делегация приехала в посольство.
вы
you (plural or formal)
в
in / to (direction)
должен
must, have to
приехать
to arrive (by transport, pf)
Questions & Answers about Вы должны требовать, чтобы официальная делегация приехала в посольство.
Why is приехала in the past tense if the demand is for them to come in the future?
This is the core rule for sentences expressing a demand, wish, or request involving a new subject. After чтобы, you must use the past tense form of the verb (приехала). Even though English uses the base verb "come", Russian grammar requires this past tense form to create the subjunctive mood.
Could we use an infinitive after чтобы in this sentence?
No, because the person demanding and the person arriving are different. "You" (вы) are making the demand, but the "delegation" (делегация) is doing the arriving. When the subject changes across the two parts of the sentence, you must use a new subject followed by a past tense verb (делегация приехала), never an infinitive.
Why use the imperfective verb требовать instead of the perfective потребовать here?
Using требовать suggests an ongoing policy or a general rule, such as "it must be your standard practice to demand this." If this were a one-time instruction for a single, immediate event, the perfective потребовать would be used.
Why is it в посольство and not в посольстве?