pour water and vegetable oil into a glass
3.把一支粉笔放入水中put a piece of chalk in water
4.把淡水装入杯子 fill one glass with fresh water
5.保护我们这个星球上的水protect the water on our planet
6.把杯子翻转 turn the glass upside down
8.用这种方法使用水use water in this way
10.大约30亿年前 about three billion years ago
marine life is incredibly rich and varied
12.范围从微生物一直到巨物ranges from the tiniest plankton all the way up to giants
13.水的化学结构 the chemical structure of water
give water it unique properties
15.由两个氢原子和一个氧原子组成be made up if two hydrogen atoms and one oxygen atom
16.一种极性微粒 a polar molecule
break down both solids and gases
18.为其他生物所利用become available to other living creatures
water is a liquid at room temperature
have a relatively high freezing point
21.与纯水混合 mix with pure water
the salinity of the earth’s oceans
be measured in kilograms per cubic metre
take advantage of the density of water
25.能量 the amount of energy
26.把温度提高1℃ raise the temperature by one degree centigrade
27.释放出大量的热 give off a lot of heat
28.对温度的巨变和突变很敏感be sensitive to large and sudden changes in temperature
keep steady by absorbing and giving off heat
add energy to the marine ecosystems