Yun Yun is the little "gourmet" in the class. She wants to taste every kind of food, but she doesn't know much about it and can't even keep it.

The typical food of the first dry storage method-dried fish, dried shark's fin and dried vegetables.

The second typical food preserved by cold storage-quick frozen jiaozi, watermelon, fresh tomatoes and fresh milk.

The third typical food preserved in vacuum-biscuits, canned fruits, pickles, radishes and pickled cucumbers.

Canned pickled mustard tuber jam ham.

Note: the food provided above does not need to be heated for preservation.