2. The intended readers of the passage are____.

1. The three facts presented in the passage are used to illustrate that ____.

4. an important part of our nation’s energy supply

3. our pollution problems

2. It will run for another several billion years

1. It can help us save our precious fuel

4. Solar energy is now in its infancy, but it will be considered as ____________.

Keys:

3.We don’t need so much energy if we solve ___________________________.

2.How long will the sun run for ?

1.What can solar energy help us to do ?