Questions & Answers about De kerk is erg mooi.
Is erg a form of the word er that we are learning in this lesson?
No, it is just a coincidence that they look similar! Erg is an adverb meaning "very" (it can also mean "bad" or "terrible" in other contexts). It has nothing to do with the place replacement word er (there) from this lesson.
Can I use heel instead of erg to say "very"?
Yes, absolutely! Heel mooi and erg mooi both mean "very beautiful" and you will hear Dutch speakers use them interchangeably.
Why doesn't mooi have an -e added to the end here?
Adjectives in Dutch only get an extra -e when they are placed directly before the noun they describe (like in the phrase de mooie kerk). When the adjective comes later in the sentence after a verb (like is), it always stays in its basic, uninflected dictionary form: mooi.