【正确答案】Energy
Energy makes the world go. It is indispensible to both animal life and human life. In the hot summer when there is a power breakdown we feel all the more the need for electric energy which powers the electric fan and air-conditioner.
There are different sources of energy. The rivers and streams are a good source for electric energy. The sun provides us with light, heat and electricity. The energy can be changed from one form to another. It can never be exhausted nor reproduced. It just goes on changing in cycles.
It is important for us to make use of energy. Solar energy is being made to generate electricity, to cook and to bathe. Atomic energy is used in industry and aviation and many other fields. We are now doing our best to make energy serve our people in every way possible.