Present Perfect vs Past Simple 2

Rewrite the following sentences, using Present Perfect or Past Simple. You may have to change some of the words. ANSWERS + EXPLANATION
1) I last saw David when I was a child.
I a child.
2) Mr Duke bought a car three months ago.
It is a car.
3) How long is it since you visited your grandpa?
When your grandpa?
4) The bus didn't come for over an hour.
It was over .
5) She has never been to a French restaurant before.
It's a French restaurant.
6) Sandra started to work at the post office two years ago.
Sandra two years.
7) It's the first time I have had an accident.
I before.
8) How long is it since you left university?
How long university?
9) It's years since the professor gave a lecture.
The professor years.
10) When was the last time Mark had a haircut?
When a haircut.