Choose the right form of the verd and write down the

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 безотлагательно!!! Взарание громадное спасибо!!!
тут надобно перевести задание на верху и выполнить его