It is adj. (for.../ of...) to do sth.The structure4. It is fantastic to work as a volunteer.3. It is interesting to become a volunteer.2. It is necessary to help him.1.It is meaningful to do something for the Olympics.1. 为奥林匹克运动会做事是有意义的。2. 帮助他是必须的。4. 成为一名志愿者是很有趣的。3. 作为一个志愿者工作是极好的。cheap, convenient, dangerous, difficult, easy,exciting, expensive, important, interesting,necessary, normal, possible, useful, wonderfulwhat we think about someth..