thirty和thirties的區別

thirty:

n. 三十年代

num. 三十

adj. 三十個的

I usually do my homework at around five thirty.

我通常5點半左右寫作業。

thirties:

pl.三十幾三十多歲三十年代

My father has been the President of the company since he was in his thirties.

我父親三十幾歲就是公司的董事長了。