Questions & Answers about Jeg legger merke til at du er trøtt.
Å legge merke til is a fixed Norwegian expression meaning to notice, to observe, or to take note of.
You should learn it as a whole chunk:
- å legge merke til noe = to notice something
- å legge merke til at ... = to notice that ...
Even though the individual words have other meanings, the expression as a whole is idiomatic. So it is better not to translate it word for word.
Yes. Til belongs to the fixed expression å legge merke til.
A good way to think about it is like an English phrasal verb:
- look at
- find out
- notice does not work this way in English, but legge merke til does in Norwegian.
So in this sentence:
- Jeg legger merke til at du er trøtt
the til is not optional. It is part of the expression.