theo‧ry S2 W1 AC / θɪəri $ θiəri / 名词 ( 复数形式 theories )

1 [可数名词] an idea or set of ideas that is intended to explain something about life or the world, especially an idea that has not yet been proved to be true → theoretical

theory about/on

different theories about how the brain works

theory of

Darwin’s theory of evolution

theory that

the theory that light is made up of waves

2 [不可数名词] general principles and ideas about a subject :

Freudian theory has had a great influence on psychology.

political/economic/literary etc theory

I’m taking a course on political theory.

3 in theory something that is true in theory is supposed to be true, but might not really be true or might not be what will really happen 反义词 in practice :

In theory, everyone will have to pay the new tax.

4 [可数名词] an idea or opinion that someone thinks is true but for which they have no proof

theory that

Detectives are working on a theory that he knew his murderer.

COLLOCATIONS

动词

come up with/develop a theory These birds helped Darwin develop his theory of natural selection.

test a theory Researchers gave workers a questionnaire to test that theory.

prove a theory No evidence emerged to prove either theory.

support a theory Modern research strongly supports this theory.

disprove a theory ( also refute a theory formal ) (= show that it is wrong ) Later experiments seemed to disprove the theory.

discredit a theory (= make people stop believing in it ) These latest findings discredit his entire theory.

ADJECTIVES/NOUN + theory

a scientific theory Scientific theories can be tested experimentally.

an economic theory His economic theory assumes that both labour and capital are perfectly mobile.

a conspiracy theory (= a theory that an event was the result of secret plan made by two or more people ) A variety of conspiracy theories question the official account of President Kennedy’s assassination.

a pet theory (= a personal theory that you strongly believe ) Each of them had his pet theory on what had caused the uprising.

短语

the theory of evolution/relativity etc According to the theory of relativity, nothing can travel faster than light.