------
## 最终结论
```python
def month_season(month, day):
    if (month == 'December' and day >= 21) or (month == 'January') or (month == 'February') or (month == 'March' and day < 20):
        return 'winter'
    elif (month == 'March' and day >= 20) or (month == 'April') or (month == 'May') or (month == 'June' and day < 21):
        return 'spring'
    elif (month == 'June' and day >= 21) or (month == 'July') or (month == 'August') or (month == 'September' and day < 22):
        return 'summer'
    else:
        return 'autumn'

assert month_season('January',4)==('winter')
assert month_season('October',28)==('autumn')
assert month_season('June',6)==('spring')
```