Stamp collectors collect stamps relating to a particular theme. Sport lovers may try their best to find Olympic stamps ________ by various parts of the world every four years.
This kind of animal has ______ in the world.
_____ with the size of the whole earth,the biggest ocean does not seem big at all.
What do you think of the reasons ______ he explained at the meeting ______ reducing the price?
—I've got some wonderful news.We have been invited to the palace ball. —Really?______.
The people,______ had been damaged by the flood,were given help by the Red Cross.