单选题
What do we know about the sea? Most of us have seen it. We know that it looks very pretty when the sun is lighting on it. We also know that it can be less pretty when the weather is terrible. What other things do we know about it? The first thing is that the sea is very big. Look at a map of the world and you'll find there is less land than sea. The sea covers
单选题
Which of the following is true according to the passage?