помогите пожалуйста, надо к каждому предложению задать по 5 вопросов

1) Their group is one of the best in our University.
Is their group one of the best in our University?
Which group is one of the best in our University?
Is their or your group one of the best in our University?
Their group is one of the best in our University, isn't it?
Whose group is one of the best in our University?

2) We have already seen that strange person near the bridge.
Have you already seen that strange person near the bridge?
Who has already seen that strange person near the bridge?
Where have you already seen that strange person near the bridge?
Have you already seen that strange person near the bridge or at the station?
We have already seen that strange person near the bridge, haven't we?

3) My father's best friend has been teaching German at the University.
Has my father's best friend been teaching German at the University?
Who has been teaching German at the University?
What has my father's best friend been teaching at the University?
Has my father's best friend been teaching German or English at the University?
My father's best friend has been teaching German at the University, hasn't he?

4) Helen and Ben are walking together near the park.
Are Helen and Ben walking together near the park?
Who is walking near the park?
Where are Helen and Ben walking together?
Are Helen and Ben walking together near the park or near the garden?
Helen and Ben are walking together near the park? aren't they?