My uncle lost his ID card yesterday morning.________,a schoolboy found it and sent it back to him in the afternoon.
It is clever ________ you ________ me work out the maths problem.
There is ________ in the classroom, so we can see ________.
We should prevent the children ________ the bad programmes.
The Olympics ________ every four years. And the 29th Olympics ________ in Beijing in 2008.
I think ________ necessary ________ to take more exercise.