People have been making use of these natural supplies ___1___thousands of years. ___2___ the development of technology and the increase of the population, the amount and range of materials taken has i

ncreased. It is ___3___ that this trend will continue in the years to come. ___4___, natural resources are not inexhaustible. Some resources are already nearly used up. For example, the end of the world’s fuel is already __5___ sight. Such an essential daily item as water is in short supply in many parts of the world. We can no longer thoughtlessly use many resources provided by nature. We must learn to conserve what remains.

A.with

B.estimated

C.however

D.within

E.for