Question

Change to negative and questions from.
They know a lot of people.

You work in a hotel.

He is at work at 8:30.

There is a big three in the yaed

There are eleven players an a soccer team.

There is a flight at 10:30.

Answer 1

Solo te digo las dos primeras porque no subiste los puntos...
1 - They didn´t know a lot of people.
Did they know a lot of people?
2 - You didn´t work in a hotel.
Did you work in a hotel?
3 - He didn´t is at work at 8:30.
Did he is at work at 8:30?

Answer 2

1. They do not know a lot of people.
Do they know a lot of people?

2. You do not work in a hotel.
Do you work in a hotel?

3. He is not at work at 8:30.
Is he at work at 8:30?

4. There is not a big tree in the yard.
Is there a big tree in the yard?

5. There are not eleven players in a soccer team.
Are there eleven players in a soccer team?

6. There is not a flight at 10:30.
Is there a flight at 10:30?

El comentario anterior estaba gramaticalmente incorrecto, ya que tú escribiste las oraciones en present simple.