Questions & Answers about Eru þeir með óþol fyrir mjólk?
Why use eru ... með instead of the verb hafa?
In Icelandic, the verb hafa is mostly used as a helper verb (like 'have done') or for abstract concepts. To express that someone physically possesses something, suffers from a condition, or has an allergy or intolerance, you use vera með (to be with). So, 'they have an intolerance' becomes þeir eru með óþol.
Why is fyrir used here to mean 'to'?
Prepositions rarely translate one-to-one between languages! While in English we say someone has an intolerance 'to' something, Icelandic pairs the noun óþol (intolerance) with the preposition fyrir (which usually translates as 'for').
What case does fyrir take in this sentence?
Here, fyrir governs the accusative case, so mjólk is in the accusative (which happens to look exactly the same as its nominative dictionary form). Notice that unlike the complex prepositions you are learning in this lesson which force the genitive case, the simple preposition fyrir here takes the accusative.