Some examples of le cloisteáil from the NEID show the different ways that you can express this in English:
"music played cheerfully in the background" - bhí ceol taitneamhach le cloisteáil sa chúlra (there was enjoyable music to be heard in the background)
"the bray of the trumpets could be heard" - bhí blosc na dtroimpéad le cloisteáil (the bray of the trumpets was to be heard)
"all he can hear is nothingness"- níl faic le cloisteáil aige (there is nothing to be heard by him)
"there were lots of bitchy comments" - bhí neart gangaide le cloisteáil (lots of bitchy comments were to be heard)
Thank you. I was confused about how to interpret this sentence at first, but then I saw that Duo accepts "The radio can be heard." in addition to "The radio is to be heard" (maybe it didn't before ?). After having a look at the more up-to-date German version of GnaG, it indeed really seems to be the correct interpretation (possibility ; not necessity) for this sentence. From what I read there, the meaning of such a sentence depends on the particular verbal noun used and on whether it's transitive or intransitive.
"The radio is to be heard" might be a slightly old-fashioned construction, but it seems perfectly reasonable to me - maybe it just makes more sense in Hiberno English, though "the radio can be heard" might be more common nowadays, even though you might expect "the radio can ..." to be is féidir leis an raidió ...
Go raibh maith agat a Knocksedan, bíonn do chuid ráiteas an-úsáideach ! I’m not a native English speaker and I actually didn't know that this [be + to + infinitive] construction could be used in this sense (I am more familiar with those usages), but if you say that it’s somewhat old-fashioned, I guess that’s why
The English translation given in the exercise is 'the radio is to be heard'. In English this sentence actually means 'the radio MUST be heard'. You need to choose one of the more correct english translations from the suggestions given by others in this discussion e.g. the radio is audible; the radio can be heard etc. Once again I ask you 'Where did you learn your English - because you show a deplorable lack of understanding the nuances of the English language! Being marked incorrect because your English is faulty is not fair to learners!"