theory
noun [ C or U ] uk/ˈθɪə.ri/ us/ˈθɪr.i/
B2 理论;学说;意见
a formal statement of the rules on which a subject of study is based or of ideas that are suggested to explain a fact or event or, more generally, an opinion or explanation
economic theory 经济理论
scientific theory 科学理论
Darwin's theory of evolution 达尔文的进化论
He has a theory that the hole was caused by a meteorite. 他认为那个洞是陨石坠落形成的。
in theoryB2 理论上，从理论上讲
If something is possible in theory, it should be possible, but often it does not happen in that way.
In theory, the journey should take three hours, but in practice it usually takes four because of roadworks. 按理说行程应该只要3小时，但由于道路施工，实际上通常会需要4小时。
- More examples
- It was Ptolemy who propounded the theory that the earth was at the centre of the universe.
- This new evidence lends support to the theory that she was murdered.
- This research seems to give some validity to the theory that the drug might cause cancer.
- In Jungian theory, there are certain archetypes of human personality.
- In theory, women can still have children at the age of 50.