Is it possible to enjoy a peaceful life in a world that is increasingly challenged by threats and uncertainties from wars, terrorism, economic crises and a widespread outbreak of infectious diseases?
2016年6月四级真题（第二套）阅读 Section B
柯林斯高阶英汉双解学习词典释义
N-VAR
不确定；犹疑
Uncertainty is a state of doubt about the future or about what is the right thing to do.