The sea looks very beautiful when the sun is shining on it. But it can be very terrible when there is a strong wind. The sea is very big. It covers three quarters of the earth. The sea is also very deep in some places. In one place, the sea is about 11 kilometres deep. The highest mountain(山) in the world is about nine kilornetres high. If that mountain was put into the sea at that place, there would still be two kilometres of water above it!
In most parts of the sea,there are plenty of fishes and plants (植物). Some live near the top of the sea.Others live deep down. There are also a lot of small living things,and lots of fish live by eating them. The sea can be very cold. When people go down, the sea becomes colder and colder. Only some men can go down into the deep sea. But,in 1970,five women scientists lived in the deep sea for fourteen days.