_______from the moon, our earth, with water _____about 70 percent of its surface, appears like a blue ball.

The three backpackers finally reached the top of Mount Huangshan, ________ they could enjoy the breathtaking sights to their heart’s content.

Schools have rights to their own rules based on the general conditions of the students．

island atourist attraction, last week’s earthquake would have caused far more deaths.

________we went to visit Professor Smith,he________his research work.