thirties
noun [ plural ] uk/ˈθɜː.tiz/ us/ˈθɝː.t̬iz/
B2 三十多岁
A person's thirties are the period in which they are aged between 30 and 39
My brother is in his thirties. 我弟弟三十几岁。
the thirties （温度）三十多度
the range of temperature between 30° and 39°
The temperature is expected to be in the thirties tomorrow. 明天温度预计为三十几度。