Подчеркните в следующих предложениях инфинитив и определите его форму и функцию

[екатерина1995]

To grant pardon is the prerogative of the Crown. 2. They must have been
arrested over a year ago 3. The victim is the first person to be unterviewed. 4. He seems to be unvestigating a criminal case. 5. A student must pass a group of examinations to obtain a law degree. 6. The aim of the preliminary investigation is to draw up an indictment