名词

1. 理论;学说
A theory is a formal idea or set of ideas that is intended to explain something.

2. 观点;见解
If you have a theory about something, you have your own opinion about it which you cannot prove but which you think is true.

3. (实践科目、技能的)理论基础
The theory of a practical subject or skill is the set of rules and principles that form the basis of it.

4. 从理论上说;照理说
You use in theory to say that although something is supposed to be true or to happen in the way stated, it may not in fact be true or happen in that way.

1. a tentative insight into the natural world
a concept that is not yet verified but that if true would explain certain facts or phenomena

e.g. a scientific hypothesis that survives experimental testing becomes a scientific theory
he proposed a fresh theory of alkalis that later was accepted in chemical practices

Synonym: hypothesispossibility

2. a belief that can guide behavior

e.g. the architect has a theory that more is less
they killed him on the theory that dead men tell no tales

3. a well-substantiated explanation of some aspect of the natural world
an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena

e.g. theories can incorporate facts and laws and tested hypotheses
true in fact and theory