Functions and notions
Shock and surprise
We can use the following expressions to express shock
  and surprise.
It's shocking to think 
  It's horrifying to think + (that)
  + noun
  It's incredible to think
  -  It's shocking to think that
    people kill for money.
-  It's horrifying to think
    children could be killed.
-  It's incredible to think Jim is now a millionaire.
 It's + adjective + to
  infinitive
  -  It's stupid to play with elevators.
-  It's dangerous
    to throw things out the window.
 Noun + be a real worry for + noun
  -  Teenage elevator-surfing is a real worry for parents.
-  Jack's unreliability is a real worry for
    the company. 
 It's only a matter of time + before
  / until
  -  It's only a matter of time before
    someone gets killed.
-  It's only a matter of time until
    he realizes his mistake.
 Before is more common than until
  in this construction.