What is the first thing the reader should do to understand an unknown word?

check the meaning
memorize the word
predict the meaning
study the word closely

The correct answer is: check the meaning.

Explanation:

When we see an unknown word in one text, the first thing we should do is check the meaning of the word in a dictionary. After that, we should memorize the word and try to use it in a certain context, in order to make sure we understood its meaning.

When we are predicting the meaning of the word, we can often make a mistake, because some words and their meanings can be quite unpredictable or illogical if someone doesn't know the etymology of the word or doesn't understand the scope of its use.

we flew to the Dublin Airport in the Ireland

type of determiners demonstrative