Jack is not sure if he (be) in London next week

Answer:

Jack is not sure if he is in London next week.

There are many attractions in London. TheTower of London is one of the oldest buildings in England.On the banks of the River Thames, not far fromthe tower, is the Palace of Westminster, wherethe meetings of the British Parliament are held.One of its towers is the famous watch ofEngland Big Ben. Nearby is the Ferris Wheel"Eye of London"-the largest in the world.Also very popular is Buckingham Palace-theofficial residence of the Queen in London.Trafalgar Square is the central square of thecity, next to it stands the National Gallery, nearwhich is the Church of St. Peter.

I can fly wherever I want
I get to Berlin by means of car
I go to the swimming pool every day
We have a lot of wonderful friends
I know what you did last summer
I flew to Egypt last summer
We got to the zoo yesterday
You went to the cinema few weeks ago
He had a toothache yesterday
If I knew about it I would rather go to the cinema
I have flown to Italy
We have got/gotten the first place in the race
If I had gone you would have done it perfectly
I had many duties yesterday
I have been known about it since childhood