1. All nations in the world should _________ (加强)unity and understanding in order to live a better life.
2. The old man tried to convince us of his _________ (适合) for the travel.
3. _________ (参加)in class activities is very important for your popularity.
4. Only when you have a _________ (积极的) attitude to life can you live a happy life.
5. Something must be done to _________ (保证) the safety and property of the ordinary people.
