✨ ベストアンサー ✨
(1) → It is a surprising fact.
(2) → All of us removed the fallen leaves.
If it is a proverb (ことわざ), "a" should be used instead of "the":
(3) → No one lives in a burning house.
If you are talking about a specific house that was abandoned because it burned down:
(3) → No one lives in the house that burned down.
(4) → We know the girl (who is) wearing glasses.
more natural: We know the girl with the glasses.
ありがとうございます!