Distinguished guests, today I want to tell you about renewable energy and non-renewable energy. Fossil energy is non-renewable energy. These include: oil, coal, natural gas. They can be used to generate power, generate electricity or operate large machines. Unfortunately, they are toxic to the environment. Vietnam still depends mainly on non-renewable energy sources, but water energy is also being increasingly used. Hydropower and nuclear can generate a lot of energy. They are abundant and can recover. However, hydropower is limited because dams cannot be built in some areas. Nuclear power can provide enough electricity for the needs of the whole world but it is very dangerous. The sun and the wind are alternative sources of energy. Wind rotates turbines and generates electricity. Solar energy can be converted into electricity. It can be used to heat or cool our homes. Despite some inconveniences, these alternative energy sources can bring a lot of safe and clean electricity. They will become increasingly important in Vietnam in the future.
The world " It " in the fourth pẩgraph means :
A. The sun B. The wind C. The solar power D. Electricity