Rock-climbing is a breathtaking activity, very popular nationwide among young people, ______ cooperation as well as courage plays an important role.

It is_______ that I can still remember_______ was discussed at the meeting.

I will be free then. I don’t know_______ for my holiday.

下列词语中加线的字，读音完全相同的一组是(　　)

Professor Hunter was soon told ____he discovered was not important to them