Had it been possible I would have gone to the movies but I _____ busy.

Will you please keep _____, Tom? Your father is sleeping in the room. [ ]

The computer system ________suddenly while he was searching for information on the Internet.[ ]

Since it was started in 1989, Project Hopehas received over 1.5 billion yuan ________ from home and overseas.

___ there are certainly times when giving up trying is the right thing to do, in most cases all needed is commitment and communication.