In my opinion, there are many reasons why mobile phones are dangerous. First mobile phones can cause health problems. when we were talking on the phone for a long time to have a headache. And doctors believe that using mobile phones while turn off the lights may cause blindness. Secondly,I think that mobile phones can cause an accident. If we use a mobile phone while the battery is charging can cause a bomb. Or use the phone, then walk across the road may be hit by a car. Finally, mobile phone is a device that can carry electricity as well. So we should not use mobile phones while the rain and near the high voltage post.