We Are Wondering 学无止境 When the weather is hot, you go to a lake or an ocean.Why?The sun makes the earth hot ,but it cannot make the water very hot. Although the air over the earth goes up . Then the cool air over the water moves inan takes the place of thr air . When you are near a lake or an ocean , you feel thr cool air when it moves in . You feel the wind. And the wind makes you cool. Of course, sclentists can not answer all of our questions. If we ask, :'Why is the ocean full of salt(盐）?' Scientists will say that the salt comes from rocks. When a rock jets wery hot or very cold ,it cracks(裂开），Rain falls into the cracks.The rivers carry the salt into the ocean?The ocean does mot get more salty every year.'Scientists are not sure about the answer to this uertion. We know a lot about our world .But there are still many answers that we do not have .we are wondering all the time.