Breakdown of To głupia wymówka, bo mogliście zdążyć na pociąg.
to
this
na
on, at / to (motion toward) / for (a meal) / for (waiting for)
pociąg
train
móc
to be able to
Questions & Answers about To głupia wymówka, bo mogliście zdążyć na pociąg.
Why is the verb mogliście used here, and how is it formed from móc?
Mogliście means "you (plural) could". The verb móc (can/to be able to) has a tricky past tense. For groups of people that include at least one male, the stem changes to mogli-. Then we add the ending -ście to show it means "you (plural)". If the group consisted only of women, the stem would be mogł- instead, making it mogłyście.
Why does the first part of the sentence say To głupia wymówka instead of To jest głupia wymówka?
Why is zdążyć in its dictionary form here?
Just like in English, when you use a modal verb that expresses ability or possibility—in this case, mogliście (you could)—the main action verb that follows it must stay in its infinitive (dictionary) form. That's why we use zdążyć (to make it in time).
Why do we use the preposition na before pociąg?