_________ isunknown to us all

Cindy shut the door heavily and burst into tears. No one in the office knew _____ she was so angry.

We’ll never forget this terrible accident and thedamage_______has caused to the area

There was a(n)________silence in the live interview，when no one knew what to say to the audience.

.My cousin keeps the photo____he can see ite veryday, as it always reminds him of His college days in Florida.