theory

理論、學說

His theory of evolution changed the way we see nature.

他的演化論改變了我們看待自然的方式。

理論、學理

In music, theory and practice should go hand in hand.

在音樂上，理論與實作應該並重。

看法、推測、說法口語

My theory is that she quit because of her boss.

我的猜想是，她辭職是因為她的主管。

理論上、照理說

In theory the plan works, but nobody has tried it.

理論上這個計畫可行，但還沒有人試過。