People spend hours talking on their mobile phones. There is an opinion that it may be ___HARMFUL___ to their health, but it is difficult to know for sure. Some research shows that mobile phones may cause brain problems. On the other hand, some doctors say mobiles are not ___DANGEROUS___ at all. No matter what doctors say, it’s just ___IMPOSSIBLE___ to live without a mobile phone today. It has become a very ___USEFUL___ device and people can’t do without it. It makes our life ___COMFORTABLE___ and saves time. People can get in touch with each other quickly. Mobile phones make ___COMMUNICATION___ easier.