1. This is sour milk.
    这是酸牛奶。

2. In my mouth I have a sour, vinegar taste coming from the pit of my stomach.
    我嘴里有一股从胃底涌上来的酸酸的醋味。

3. For the grave farmer he used his dentist, a sour-looking man. For the woman standing alongside him, the artist chose his sister, Nan.
    为画神色严肃的农夫，他选择了他那表情木讷的牙医，至于站在他身边的农妇，他选择了自己的姐姐南。