30的英文是：thirty.

了解：

She thinks nothing of walking thirty miles a day.

她认为一天步行三十英里不足为奇。

By sunset we had covered thirty miles.

到日落时我们已走了三十英里。

相关介绍

only thirty students graduated in Chinese last year.

去年只有三十名学生获得汉语学士学位。

The driver was a trim young woman of perhaps thirty.

驾车者是一位大约三十来岁的苗条年轻女子。

If I might hazard a guess , I'd say she was about thirty.

让我来猜的话，我说她大约三十岁。

Yesterday no fewer than thirty climbers reached the summit.

昨天不少于三十名登山者到达了顶峰。

The Tornado was about thirty feet from Mace's right wingtip.

“龙卷风”离“梅斯”的右机翼尖约三十英尺。