Hours of playing violent video games can affect the way the brain works, ______ damage to certain cells of brain.
The buses, ____were already full, were surrounded by an angry crowd.
Can you solve such problems ___raised by the audience?
We often think of the days ___we spent together on the island.
Air, _ __we breathe every day, is around us all the time.
The radio set __ _ last week has been out of order.