阅读：辨别事实与观点 — 英语填空题
题目
Read the two sentences and decide whether each is a fact (F) or an opinion (O). (1) The world's population reached eight billion in 2022, according to the UN. (2) Life today is far more stressful than it was fifty years ago. In the blank, write the two letters in order, separated by a comma: ___.