在文献综述的写作中，下面哪种情况适合用现在完成时？

在文献综述的写作中，下面哪种情况适合用现在完成时？
A.It is used when summarizing an area of research in the literature review.
B.There is no specific date or time you can refer to in the beginning of the literature review.
C.It is used when referring to someone’s views，positions or arguments，especially when comparing positions in a debate.
D.The research referred to is recent，or is more indicative of the present state of knowledge.
正确答案：It is used when summarizing an area of research in the literature review.There is no specific date or time you can refer to in the beginning of the literature review.It is used when referring to someone’s views，positions or arguments，especially when comparing positions in a debate.The research referred to is recent，or is more indicative of the present state of knowledge.