There has been a change in doctors'understanding of the cause of stomach ulcers.
A、True
B、False
C、Not Given
Doctors have been able to reduce the pain caused by stomach ulcers.
A、True
B、False
C、Not Given
下面的短文有10处空白，短文后列出12个词，其中10个取自短文，请根据短文内容将其分别放回原有位置，以恢复文章原貌。A Thirsty WorldThe world is not only hungry;it is also thirsty for water. This may seem strange to you since nearly 75%of the earth's surface is 31 with water. But about 97%of this huge amount is sea-water, or salty water. Man can only drink and use the other 3%—the ____32___water that comes from rivers, lakes, underground, and other sources. And we cannot even use all of that, because some of itis in the form of icebergs and glaciers. Even ____33___, some of it has been polluted. At the moment, this small amount of fresh water is still enough for us. However, our demand for water is increasing 34 Only if we take steps to deal with this problem now can we avoid a severeworldwide water ____35___later on. In addition to stopping wasting our precious water, one useful step we should take is to 36ways of reusing it. Today, in most large cities, water is used only 37 and it eventually returns to the sea or runs into underground storage tanks, But it is ____38___to pipe water that has been used to a purifying(净化) plant, There it can be filtered and treated with chemicals so that it can be used again just as if it were fresh from a spring. But even if every large city purified and 39 its water, we still would not have enough. Where could we turn next?To the oceans!We can make use of the vast amount of sea-water by re-moving the salt. This salt-removing 40 is already in use in many parts of the world.
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