5．
Today，an increasing number of people are always looking at their mobile phones with their heads down．These people are （71）called the"Heads-down Tribe"．Heads-down tribe members now can be seen everywhere．
There are more and more traffic accidents（72）happening because more drivers use mobile phones while driving．In order to make drivers pay more（73）attention to driving，some new traffic rules have been made．
As we can see above，using mobile phones may （74）cause traffic accidents．Also，more and more interesting and strange facts happen to the"Heads-down Tribe"．A man in America kept using his mobile phone on（75）hisway home．As a（76）result，he knocked into a big lost bear．When he lifted his eyes from the phone，he was so afraid （77）thathe turned around and ran away as （78）quickly/fastas possible．Another fact is that we can often see people in the restaurant eating face to face but looking at their own mobile phones．It's strange that they don't talk to the ones who sit opposite to them during the meal．Some of them even have （79）fun communicating with others on the phone．
Mobile phones are helpful and necessary tools for modern life．Whether they are good or not depends （80）onhow people use them．Let's be"healthy"users and try to be the"Heads-up Tribe"．
