Samuel Clemens,______ Mark Twain, wrote many popular stories.
_______from the moon, our earth, with water _____about 70 percent of its surface, appears like a blue ball.
---Have you got any particular plans for the coming holiday?---Yes. __________, I’m going to visit some homes for the old in the city.
---Have the arrangements for the concert next Saturday been all _______?---Not yet. We haven’t found a free hand.
___________in the mountain for a week, the students were finally saved by the local police .
There are some health problems that, when ____ in time, can become bigger ones later on.