This is the 466th most frequent Czech word.
mohly
"Mohly" is the feminine plural form of "moci," meaning "could" or "were able to" in English.
In this sentence, 'mohly' is used as the past tense of 'moci' (to be able to), indicating that the students (feminine subject) were allowed to or could leave for home.
Studentky mohly odejít domů po skončení přednášky.
The female students were allowed to leave for home after the lecture ended.
Here, 'mohly' is part of the conditional mood ('mohly by'), expressing a hypothetical scenario where they (feminine subject) could do something under certain conditions.
Kdyby měly šanci, mohly by se zúčastnit soutěže.
If they had the chance, they could participate in the competition.
In this instance, 'mohly' demonstrates a past tense possibility for a feminine subject, indicating that we (feminine groups) had the option to stay but chose otherwise.