a. We mustn’t hunt animals in danger of extinction.
Animals in danger of extinction mustn’t be hunted.
b. We shouldn’t throw recyclable objects.
Recylable objects shouldn’t be thrown away.
c. We should stop desertification.
Desertification should be stopped.
d. We can divide pollution into four types.
Pollution can be divided into four types.
e. We may group alternative energies in five categories: wind, solar,
biomass and hydro-electric .
Alternative energies may be grouped in five categories: ...
f. We must protect our human resources.
Human resources must be protected.
موضوع: ساعدوني 
الجمعة نوفمبر 19 2010, 20:20
