Question

Scientific Breakthroughs

Answer 1

Answer:

1a. People were able to cook by burning wood and coal

b.people were not able to work at night because they do not have electric lamps

c. oil, gas or coal may harm the earth

d. we can use less energy

2.

1. should

2.would

3. should

4.should

5. would

3.

1. b

2. b

3. c

4. b