27:Biogas is made from a mixture of methane (CH4) and some other gases arising from the decomposition of organic matter
28:Yes
29:Because it made from natural ingredients
30:it is a renewable source
31:solar energy will be used to solve the problem by we
32:a hydropower station will be built in that arena in the next year by we
33coal will be replaced by another renewable source by we
34:solar power will be used to heat the water
35:this bicycle is her
36:they will be learning English this time tomorrow
37 solar energy will be used in the future by many contry
38how long dose it take him to go to school on foot?
39people won't use flying car until the year 2050
40 I thing biogas is cheap and abundant
