IV. 閱讀測驗：以下有兩篇短文，共有 10 個題目，為第 41 至 50 題，請於閱讀短文後，選出最適合的答案。Because of the energy crisis, scientists in some industrialized nations have become greatlyinterested in the potential of solar energy. Some experts estimate that the present supply of fossilfuel will last only until the end of this century. The problem that solar energy researchers arefacing is how to utilize the sun's energy effectively and inexpensively. One of the most popularmethods currently used is rooftop solar collectors and underground storage tanks. An advantageof a properly working system of this type is that it will not create any environmental pollution.Another advantage of using solar energy is that the cost of the fuel, the sun's light, is next to zero.
41. The passage is mainly about _____
(A) the shortage of fossil fuel.
(B) the problems that energy researchers are facing.
(C) solar energy.
(D) inexpensive energy sources.