Загальна характеристика земноводних !!!! Очень надо помогите завтра олимпиада

ПОМОГИТЕ ПЛИЗ!!!ОЧ РОЧНО НАДО!!!

Раскройте скобки,употребив нужную форму причастия (Participle l или Participle ll).Письменно переведите редложения.

1)When (to ask) important questions,he frowned and answered silly things.

2)(To know) that their resurces are limited,people make a decision how to allocate them in the best possibly way.

3)(To enter) the building,he headed for the main office.

4)When (to take) the decision i made mistake.

5)This is the best method that can (to use) in order to compare the productivity of capital in different industries.