a) Did they go to Sochi last summer?

Where did they go last summer?

They went to Sochi last summer, didn't they?

Did they go to Sochi last summer or two year ago?

Didn't they go to Sochi last summer?

b) Does she often tell us funny stories?

What does she often tell us?

She often tells us funny stories, doesn't she?

Does she often tell us funny stories or jokes?

Doesn't she often tell us funny stories?

c) Will they have built a house by that time?

When will they have built a house?

They will have built a house by that time, won't they?

Will they have built a house or a hotel by that time?

Won't they have built a house by that time?

d) Are they waiting for you?

Whom are they waiting for?

They are waiting for you, aren't they?

Are they waiting for you or your sister?

Aren't they waiting for you?