As water gets colder, its temperature drops lower and lower, until it begins to freez

（) from the moon, our earth, with water （) seventy percent of its surface, appears as a “blue ball”.

It is important that the water _____ very often as this can lead to increased deposits.A.n

Set out as much as possible so that you can get there before it gets dark.（)

根据材料，回答题。 Sharks Perform. a Service for Earth"s Waters.It is hard to get people to

When a ruler is partly in a glass of water, it looks as if it______.A．breaksB．has brokenC．

As the ship is loaded, it will sink deeper and deeper into the water, but only sink deep e