Turn into affirmative form and negative form in past simple

Ex1: Turn into affirmative form and negative form in past simple
1. Nga is late for school
2. They arrive at the airport at eight o' clock
3. Mr Quang teaches mathematics for many years
4. Mr Robinson buys a poster
5. The children are very happy in their
6. She receives many gifts 
7. My brother spends his summer holiday on the farm