1, corn cooked in the northern region 10 minutes or so before it is ripe. Note that this time is calculated from the time when the water boils.

2. If it is sweet corn, it can be boiled with low heat for about 10 minute; if it is waxy corn, old corn and sticky corn, it needs to be boiled for about 15-20 minutes.

3. Corn, also known as corn and corn cob, is a panicum miliaceum of Gramineae. Native to Central America and South America, it is cultivated all over China and widely planted in tropical and temperate regions all over the world.