an idea that attempts to explain something but has not yet been tested or proved to be correct 假设；假说
Our findings support the hypothesis that these patients are at increased risk of heart disease. 我们的研究结果证明了这一假设，即这些病人患心脏病的危险增加了。
working hypothesis (=a theory that can be used although it may have to be changed later) Darwin offered a working hypothesis for the mechanism of evolution. 有待论证的假说