Сhoose the correct word

1. This summer, I'll [enrol|study] on a nursing course.
2. John [admitted|claimed] that he had made a mistake.
3. Having little money as a child has [complicated|motivated] him to succeed in life.
4. The lecturer has a very [talkative|chatty] style.
5. Danny [researched|investigated] martial arts for his assignment.
6. The lecturer had lost the interest of his [audience|crowd] after ten minutes.