thirties
When you talk about the thirties, you are referring to numbers between 30 and 39. For example, if you are in your thirties, you are aged between 30 and 39. If the temperature is in the thirties, the temperature is between 30 and 39 degrees.
Mozart clearly enjoyed good health throughout his twenties and early thirties.
莫扎特显然在二十几岁和三十刚出头时身体很好。
The thirties is the decade between 1930 and 1939.
She became quite a notable director in the thirties and forties.
她在20世纪的三四十年代成为一位名导演。
thirties
Thirty is the number 30.