Although the resource base of other fossil fuels such as oil sands, heavy oil and oil shale is very large, they are likely to supply only small amounts of energy before the year2000.
Although the resource base of other fossil fuels such as oil sands, heavy oil and oil shale is very large, they are likely to supply only small amounts of energy before the year2000.
虽然其他的矿物燃料如油砂、重油和油页岩的蕴藏量很大，但在2000年前，似乎只能供应能量中的一小部分。