Viết ít nhất 150 từ trong khoảng 20 phút.
The diagrams show a structure which uses wave power to make electricity. Diagram A shows what happens when a wave comes in, and diagram B shows what happens when the wave goes out.
Overall, the structure is built on a cliff or a sea wall, and it has a chamber, a column and a turbine. The movement of the waves pushes air up and down in the column, and this turns the turbine to make electricity.
In diagram A, a wave comes into the chamber from the sea. The water in the chamber rises and pushes the air up into the column. This air goes past the turbine and makes it turn, so electricity is produced.
In diagram B, the wave moves back out of the chamber to the sea. When the water level goes down, air is pulled down from the top of the column into the chamber. This air also passes the turbine, and the turbine turns in the same direction as before. Because of this, the structure can produce electricity when the waves come in and also when they go out.