I.1 how do you drink much water everyday?

2  have you finished your homework yet?

3 hung's uncle is a hard-working engineer

4 is collecting stamps a cheap way to learn history?

2.1 ruby isn't as exciting as football

2 my hat isn't the same as hers

3 long swims badly

4 solar energy will be used to protect the environment

3.1 were bought

2 have you ever visited

3 walking

4 are

IV.1 save

2 off

3 in

4 fossil

5 of 

6 therefore

2.1 fossil fuels are oil,coal and natural gas

2 the alternative sources of energy are energy from the sun,the wind and the water

3 the sun energy is used for growing plants,evaporating water for rain and maintaing the temperature of the planet 

4 if we are able to collect solar energy we will be sure to have this abundant source of power