_____ the catastrophe happened that the local government realized the importance of substantial development.

Talking loudly in a library is impolite.—In fact, we should also take care not to cough or sneeze loudly in public.

Will you compete ______ the race? [ ]

Are they working? —No, they are talking ______ the phone.[ ]

you paint?-Yes, I can. So I want to join the art club.