Traditional works of art from different provinces ______at the culture show of the 2010 Shanghai World Expo.

The twins, Who       their homework, were allowed to play badminton on the playground.

Before the first nonstop flight made in 1949,it______necessary for all planes to land for refueling.

—Tony, come down and help me with the heavy box! — Come on! I _______ all day long．Get Peter to do that!

Had it been possible, I would have gone to attend Monica in the hospital, but I  fully occupied last month.