17. 锻炼：He takes half an hour`s exercise every day.
    Swimming in the sea helps to build up both physical strength and willpower.

    18. 发挥：Now we have every opportunity to bring our talents into full play.
    We should give full play to collective wisdom.

    19. 发生：Without newspapers we would not know what is happening in our own society or abroad. (take place, occur)
    From TV we know what is going on in the world.(from: www.entong.org)

    20. 发展：With industries and business developed quickly, the number of trees in many big cities has dramatically reduced.
    The village is growing into a town.

    21. 反映：This problem reflects that we show different attitudes towards different subjects.
    Inevitably they will give expression to their own ideologies.

    22. 丰富：Travel can widen our knowledge and broaden our horizon, and makes one open-minded as well.
    As we know, watching TV may relax our body, broaden our mind and enrich our life.

    23. 负责：Cars are responsible for most of the smog in cities, which has polluted the environment seriously.
    She is very conscientious in her work.

    24. 加强：We should strengthen legislation to confirm the publication of things, then there will be less unpleasant things. (improve)
    We should enhance combat preparedness.

    25. 坚持：Modernization will be entirely possible in the first half of the 21st century, as long as we hold an idea that economic development is the center of all our work. (from: www.entong.org)
    China in the 21st century will stick to a sustainable development strategy.

    26. 进行：A good student should take good care of his body and take some physical exercise in his leisure time in order to become a strong man.
    Their secretive behavior made me suspect there was something illegal going on.

    27. 经受：For the first time, we experienced defeat.
    The company has undergone some major changes in the last five years.

    28. 举行：The club will hold its monthly meeting next Tuesday.
    The congress took place in the Great Hall of the People.

    29. 开展：We should carry out criticism and self-criticism.
    He is very important to launch a movement for increasing production and practicing economy.

    30. 凭：What do you base this conclusion on?