题目内容：
In the coming years, the PV sector will continue to play an important role in the global transition from a fossil-based energy system to a renewable and sustainable one.
A.Explaining the significance or necessity of the research
B.Reviewing the existing literature relevant to the present study
C.Identifying a gap in the existing literature
D.Announcing the purpose/focus of the study
E.E.Outlining the paper structure
参考答案：