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