2. If you don't know the word, you should __________ it in a dictionary.

Ответ (EN):

1. If you don't know the word, you should look up it in a dictionary.

Перевод (RU):

1. Если вы не знаете слово, вам следует поискать его в словаре.

Ответ: If you don't know the word, you should look up it in a dictionary.