1. According to the passage, static electricity can be caused by_______.
[ A ] using home-made electrical goods
[ B ] wearing clothes made of natural materials
[ C ] walking, on artificial floor coverings
[ D ] copying TV programs on a computer
2. What effect does excessive positive ions have on some people?
[ A ] They think they are mad.
[ B ] They feel very tired.
[ C ] They become violently sick.
[ D ] They are too tired to do anything.
3. By Observing the behavior of animals, scientists may be able to_______.
[ A ] prevent disasters
[ B ] organize groups of people
[ C ] predict earthquakes
[ D ] control areas of California
4. A high negative ion count is likely to be found_______.
[ A ] near a pond with a water pump
[ B ] close to a slow-flowing river
[ C ] high in some barren mountains
[ D ] by a rotating water sprinkler
5. People should be able to come to a decision about ions in the air if they_______.
[ A ] note their own reactions
[ B ] move to a healthier area
[ C ] observe domestic animals
[ D ] watch how wealthy people behave