外出旅游时最好带上手机，以防出现紧急情况

问题描述：

问题解答：

In case of emergencies ,you'd better take your mobile telephone with you when you go out for a trip.

You'd better take your mobilephone with you when you are travelling,to be ready for emergencies.

Bring out the best cell phone when traveling to prevent emergency situations

You'd better carry the cellphone with you when you are going out for a trip in case that emergency appears.