Scientists and members of the public are becoming increasingly concerned about the effects on mental， emotional and physical health of electro-magnetic fields emanating from power lines， mobile phones， computers and sub-stations， to name but a few devices that use and channel electricity.
Electro-magnetic fields are invisible to the naked eye. However， their presence in homes， offices and factories， in strong forms， is increasingly being shown to be harmful to our health. American and Scandinavian research shows how electro-magnetic stress can contribute to insomnia， lethargy， depression， allergies， headaches， learning problems， aches and pains in the joints and more serious illnesses such as cancer and me.
It is our contention that not enough emphasis has been placed on the interaction between man made frequencies such as radio， microwave and electro-magnetic and the earth's natural magnetic and electric fields and the effects of this interaction on health.
There are simple measures that can be taken in the home to reduce the electro-magnetic fields. It is advisable to remove all plugs from their sockets when electric machines are not in use. Our measuring instruments show that this is far more effective in reducing electro-magnetic fields than just turning off the socket switch on the wall. The bedroom is the most important area to be free of electro-magnetic bombardments. At night the body repairs its cells. However， if the body is being bombarded by electro-magnetic fields this function can be impaired.
It is therefore important not to use any plug sockets immediately behind the bed during the night owing to electro-magnetic fields being emitted. Electric blankets when not unplugged at the wall still emit a high level of electro-magnetic radiation even when the switch is in the off position. This means that the body is constantly getting a dose of electro-magnetic radiation all night which can impair sleep， cause a feeling of lethargy the next morning and can eventually affect the immune system and hormones in the body. Electric alarm clocks can also cause a wide band of electro-magnetic stress in the head area. These clocks are best moved to about four feet away from the bed or replaced by a battery only alarm clock. Similarly the bedroom television also needs to be about 6 feet away from the bed. Electrical installations on the wall immediately behind or next to the bed are also relevant here. Where there is a computer， for example， in the next room close to the bedroom wall this may well cause electro-magnetic fields to radiate through the wall to the bed area. Computers can also link with televisions and electrical kitchen equipment to cause distorted fields.
1. It can be inferred from the text that electric devices are
[A] perfect modern inventions.
[B] all invisible health killers.
[C] almost all mixed blessings.
[D] all directed magnetically.
2. The text indicates that electro-magnetic fields
[A] exist everywhere on the globe.
[B] seem inescapable to modern people.
[C] can be eliminated intentionally.
[D] may be adjusted to the survival of life.
3. The author appeals for sufficient awareness of the
[A] mutual interference from household electric appliances.
[B] interaction between radio frequency and earth magnetism.
[C] harmful results of man-made and natural electric fields.
[D] joint effects of artificial and natural electro-magnetic fields.
4. The proposed measures to reduce the harmful effects include
[A] unplugging the machine when it goes out of use.
[B] freeing the bedroom of electric appliances at night.
[C] switching off the apparatus when it quiets working.
[D] disconnect electric devices immediately after working.
5. The bedroom needs protection from man-made fields because
[A] our health is more readily harmed during our sleep
[B] its walls can hardly hamper the radiation of the fields.
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