New sources of energy must be found, and this will take time, but it is not likely to result in any situation that will ever restore that sense of cheap and plentiful energy we have had in the times past. 该句属于哪种句子结构类型：
举一反三
- Our energy needs will have to be fulfilled from ( ) A: depletable energy sources B: renewable energy sources C: the existing energy D: recycling energy
- People are beginning to use clean energy sources mainly because _______. A: fossil fuels have caused a lot of pollution B: clean energy is cheap C: fossil fuels have cost a lot of lives D: they do not have enough fossil fuels now
- We had a good time there, and the food was plentiful and ( ).
- We have to prepare for a new age of energy synthesis since fossil fuels will be eventually depleted.
- ______ is an energy form found in nature that has not been subjected to any human engineered conversion process. It is energy contained in raw fuels, and other forms of energy received as input to a system.( ) A: Premium energy B: Primary energy C: Principal energy D: Preliminary energy