a sour flavour的用法和样例：
- This bacteria not only gives a sour flavour to matured kimchi but also prevents excessive fermentation by restraining growth of other bacteria.
- This milk has gone sour; it has a sour taste.
- I received a sour look every time I past her house.
- I never heard him make a sour expression.
- A substance having a sour taste.
- This milk has gone sour;it has a sour taste.