Listen to a guide at a glass factory talking to visitors. – Luyện nghe VSTEP Part 3 – Bài nói, bài giảng

1. Why is soda ash added to the sand?

A. to make the glass lighterB. to stop the glass from crackingC. to give the glass its colourD. to lower the temperature at which sand melts

2. What does the limestone do?

A. It makes the glass stronger.B. It makes the glass melt faster.C. It cools the glass.D. It makes the glass transparent.

3. Why are the bottles cooled slowly?

A. It gives the bottles a smooth surface.B. The machines cannot work faster.C. Glass that cools too fast may crack later.D. It saves electricity.

4. How much of the material in the furnace is recycled glass?

A. almost all of itB. about a thirdC. about a quarterD. about half

5. Why does using recycled glass save energy?

A. It is already shaped like bottles.B. It is lighter to transport.C. It melts at a lower temperature.D. It does not need to be cooled.