Choose the right form of the verd and write down the sentences.

1. We already (were, have been) to London.
2. We (were, have been) in London 5 eyrs ago.
3. They (didn*t see, haven*t seen) the Tsar Bell when they were in Moscow.
4. They (didn*t see, haven*t seen) the Tsar Bell yet.
Помогите пожалуйста срочно!!! Взарание огромное спасибо!!!
           тут надо перевести задание на верху и выполнить его