phone user is driving or riding in a car at 15 mph or more, and displays the message "Please Don't Text and Drive." The app automatically replies to incoming text messages, letting the sender know that you're driving and unable to respond immediately.Passengers can simply use the"snooze (小睡)" function to reactivate texting.The Safe Texting App is available for iPhones and Android mobile phones.

　　语篇解读：本文介绍了美国汽车配件协会为了提高交通安全推出的一款免费软件，以此来减少司机在驾驶时使用手机造成的事故。

　　4．Why does distracted driving mostly affect teen drivers?

　　A．Because they can only rely on texting for communication.

　　B．Because they lack enough driving experience.

　　C．Because they often talk on the mobile phones.

　　D．Because they are mostly affected by other drivers.

　　解析：选B　细节理解题。根据第二段"Distracted driving is often considered a problem that mostly affects younger drivers ... Because these drivers are typically less experienced than older drivers, distractions like texting present great risks."可知，分心驾驶主要影响的是年轻司机，因为他们缺乏驾驶经验。

　　5．What is the third paragraph mainly about?

　　A．Distracted driving has been a serious safety problem.

　　B．Older drivers like texting better than younger ones while driving.

　　C．Safe Texting Campaign has done much research into distracted driving.

　　D．Distracted driving often affects younger drivers greatly.

　　解析：选A　段落大意题。根据第三段内容可知，犹他州的一个大学的报告显示，开车时用手机会降低人体反应速度，程度等同于血液内酒精含量0.08%。警方报告的交通事故中，有四分之一是由分心驾驶引起的，而致死的交通事故中有16%是由于司机分心。由此可知第三段主要说明分心驾驶一直以来都是一个严重的安全问题。

　　6．How does the free Safe Texting App work?

　　A．It can stop drivers from texting messages.

　　B．It will turn off your phones if you text while driving.

　　C．It will remind you to drive carefully.

　　D．It can detect your distraction and stop the car.

解析：选C　细节理解题。根据第四段"The app simply detects when the mobile phone user is driving or riding in a car at 15 mph or more, and displays the message'Please Don't Text and Drive.'"可知，这款软件会在司机的驾驶速度在每小时15英里或更高的情况