What do you know about the sea? Some people often see it, _______ others don’t. The sea looks beautiful _______ a fine sunny day. Millions of people hope _______ their holidays by the sea. They can swim in or lie (躺) on the beaches in the sun. They enjoy themselves there. But it can be very terrible _______ there is a strong wind you know about _______?

Of course, the sea is very large. Looking _______ a map of the world, you can see it is much bigger than land. There _______ a lot of islands in the sea. Some are big and some are small.

Did you _______ in the sea? If you answer “Yes”, you may know that the water is salty. Rivers _______ salt from the land to the sea. Some places of the sea are saltier than other places. Do you know the Dead Sea (死海)? Fish can’t live in it. However, ________ is afraid to sink (下沉) in the Dead Sea. Why? Because people would float (漂浮) in it.

   The polar bear (北极熊), in fact, does not have white fur. Usually after a meal, polar bears have a short sleep. A polar bear can have 2 to 3 babies at a time. They live with their mothers until they are about two and a half years old.

However, polar bears will die out (灭绝) soon because of people. There are only 20,000 to 25, 000 polar bears in the world. They are trying hard to survive today. The number of polar bears is becoming smaller and smaller because of the loss of sea ice (海冰的消融).And polar bears mostly live on the sea ice, not on the land ice. Global warming makes the sea ice less and less.

Don’t you want to save polar bears? Don’t you want to make the world a better place for all living things? Do not just sit there and wait. Let’ s start doing something to protect the environment! Take the bus more often from now on, turn off the light when you don t need it, and try to make less rubbish... Every small thing can be great! Join me and save the polar bears, and, of course, the tigers, the giant pandas and all other animals that are in danger.