teach one's granny how to suck eggs

例句：

1. 1. I teach English to my students every day.
   我每天给我的学生教英语。
2. 2. The teacher explained the problem in detail.
   老师详细解释了这个问题。
3. 3. She taught me how to cook a delicious meal.
   她教我如何做一道美味的菜。