.Everyone knows that _______ is dangerous to play with fire, but _______ is difficult is to prevent children from playing with fire.
—Why isn't the recorder ready yet? —I'm sorry. It________in the shop.
As a result of the use of the new technology, the production of this product________50 percent.
Millions of pounds' worth of damage________by a storm which swept across the north of England last night.
All the gifts must be mailed immediately________in time for Christmas.
If city noises________from increasing, people________shout to be heard even at the dinner table 20 years from now.