thirty

英 [θti] 美 [θrti]

num.

三十;三十几;三十年代

复数： thirties

例句：

The association between the two companies stretches back thirty years.

这两家公司的往来可以追溯到30年前。

I know that you've been studying chimpanzees for thirty years now

我知道你研究黑猩猩至今已有30年了。