Прошу, помогите! Выберите правильную неличную форму глагола.
It is difficult (...) an active element for a compound.
1) having liberated
2) to liberate
3) liberating

(...) all the examinations he left for his native town.
1) To have passed
2) Having passed
3) Passing

Выберите правильный вариант неличной формы глагола.
We request for the money (...) before the end of the month.
1) to be transferred
2) transferred

They happened (...) her at the conference on computer security.
1) meeting
2) to meet