我认为手机对我们是有用的。例如，我们可以用手机来放松我们自己。我们也可

I think cell phones are useful to us. For example, we can use a mobile phone to relax ourselves. We can also use it to check information online. But I don't think students can use mobile phones at school. Because it would be that the students could not study well. They may send messages and play games on their phones. They may even use their mobile phones to search for answers during exams. That is bad for students.

I think mobile phones are useful to us. For example, we can use our mobile phones to relax ourselves. We can also use it to look up information on the Internet. But I don't think students can use their mobile phones in school. Because that's why students can't study hard. They may send messages and play games on their phones. They may even search for answers on their mobile phones during exams. That's bad for students.

I think mobile phones are useful to us. For example, we can use mobile phones to relax ourselves. We can also use it to search information on the Internet. But I don't think students can use mobile phones in school. Because it will make students unable to study hard. They may send messages and play games on their phones. They may even use their mobile phones to search for answers during exams. That's bad for students.