A. SO OFTEN B. AS OFTEN C. SO OFTEN AS D. AS OFTEN AS A. SO OFT...

98. A. so often

B. as often

C. so often as

D. as often as

Choose (A, B, C or D) to complete the passage:

There is now increasing concern about the world’s energy (99) ………

particularly about those involving fossil fuels. Unless than a hundred years we shall

probably (100)……… all the present sources of oil and gas. The world’s coal

reserves should last longer but once used, these can’t be (101) ………. It is

important, therefore, that we should develop such alternative sources of energy as

solar energy and nuclear energy as well as water and win (102) ……… class as

renewable energy. Until these energy supplies are widely used, it is important for the

develop countries to reduce energy (103) ……… as much as possible.