III. There is a mistake in each sentence. Find and correct it.
1. He said he is sure of the plan.
2. Jack's parents are very proud of their son's excellent.
3. I'll pay a visit for my grandparents tomorrow.
4. I khew him during i was a child.
5. My son is more intelligence than his
6.There are a lot of rain in Viet Nam that all the fields are flooded.