There is the appreciation of the salient historical truth ________ the aging of advanced societies has been a sudden change
正确答案： C
本题解析：
本句中 that 引导的也是同位语从句。
What are the key features of a research paper?
What are the characteristics of good writings?
How many parts does a science and technology paper consist of? What are they?
How many forms can articles be roughly divided into?what are they?
How many parts is an article usually composed of? What are they?
What are the paragraph qualities?
句子写作：My presentation seemed to go well.
句子写作：The house ____is still standing.
句子写作：The judge had a hard time deciding___________________.
