A: Read this passage carefully and answer the qutstions.
All living things need water．Fishes live in water．We need water to drink and use．Animals and plants need water，too． There are two kinds of water—sea water and fresh water．Sea water is salty and we cannot drink it．We drink fresh water．
Water is an interesting thing．When we boil water，it will turn into steam ．If we put a piece of glass over the steam ，it will cool down and turn back into water drops．If we put some water into a freezer，it will freeze and turn into ice．But when we take out the ice and place it on a table for some time，it will melt and become water again．
If we drop a coin into a glass of water，it will sink to the bottom ．But when we put a match into it，the match will not sink．It will float on the surface．What happens when you swim ？Do you float or sink？
1．Why can't we drink sea water？
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2．What kind of water can we drink？
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3．What will water becom e if we boil it？
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4．What will happen if we put water into a freezer？
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5．When ice becomes warm ，what will it become？
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6．What will happen if we put a coin into a glass of water？
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7．What will happen if we put a match into it？
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8．Will you float or sink when you swim in the sea？
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Key:
1．Because sea water is salty． 2．We can drink fresh water． 3．It will become steam． 4．It will freeze and turn into ice． 5．It will melt and become water again． 6．It will sink to the bottom． 7．It will float on the surface． 8．略
