Present Perfect vs Past Simple

I'm really hungry. I ....... yet.

• haven't eaten

• didn't eat

• haven't ate

They ...... a new car last month.

• builded

• built

• have built

...... Harry and Sue ever ...... a cave?

• has / explore

• did / explore

• have / explored

• have / explore

The children went to an adventure camp two years ......

• before

• ever

• ago

I ...... to the UK last year during my summer holiday.

• has gone

• went

• didn't went

How long ...... about this problem?

• she knew

• has she known

• did she know

Our neighbour ...... in hospital since Friday.

• has been

• was

• were

They ...... me at yesterday's meeting.

• hasn't recognised

• haven't recognise

• didn't recognise

We ...... her for three years.

• worked

• have worked

• work

Mr. Brown has ...... left the office.

• yet

• since

• already