The adverb clause here is <span>"since the sun came out" - it gives some information about the timing of the event.
It modifies "feels" (actually I would say that it modifies the phase "feels warmer") - this "feeling" happens since the sun came out, that's when it started!</span>
Answer:
Synonyms for "indeed" are: truly , in fact , as expected , really , surely , undeniably .
Since the instructions say use the last simple negative form, these are the answers:
1. David did not watch
2. Carol did not appear
3. did not book
4. did not close
5. did not follow
6. did not disappear
7. did not wait
8. did not recognize
9. did not identify
10. did not apologize
11. did not like
12. did not admit