A、There were fatal mistakes in its design. B、The builder didn’t observe the building codes of the time. C、The traffic load went

(20-1)The Decade for Natural Disaster Reduction is a program designed to reduce the impact of natural disasters throughout the world. With support from the United Nations, countries will be encouraged to share information about disaster reduction, for instance, information about how to plan for and cope with hurricanes, earthquakes and other natural disasters. One of the most important things the program plans to do is to remind us of what we can do to protect ourselves. For example, we can pack a suitcase with flashlights, a radio, food, drinking water and some tools. This safety kit may help us survive a disaster until help arrives. Besides, the program will encourage governments to establish building standards, emergency response plans and training programs.(20-2)These measures can help to limit the destruction by natural disasters.(21)The comparatively mild effects of the northern California earthquake in 1989, are good evidence that we do have the technology to prevent vast destruction. The recent disasters, on the other hand, prove that people will suffer if we don’t use that technology. When a highway collapsed in northern California, people were killed in their cars.(22)The highway was not built according to today’s strict standards to resist earthquakes. Individuals and governments have to be farsighted. We should take extra time and spend extra money to build disaster safety into our lives. Although such a program can’t hold back the winds or stop earthquakes, it can save people’s lives and homes.
20. What is the purpose of the program mentioned in this passage?
21. What can we learn from the northern California earthquake in 1989?
22. Why did the highway in northern California collapse?