Federal regulators Wednesday approved a plan to create a nationwide emergency alert system using text messages delivered to cell phones．Text messages have exploded in popularity in recent years, particularly among young people．The wireless industryls trade association, CTIA, estimates more than 48 billion text messages are sent each month．
The plan comes from the Warning Alert and Response Network Act, a 2006 federal law that requires improvements to the nation's emergency alert system．The act tasked the Federal Communications Commission （FCC）by coming up with new ways to alert the public about emergencies．
"The ability to deliver accurate and timely warnings and alerts through cell phones and other mobile services is an important next step in our efforts to help ensure that the American public has the information they need to take action to protect themselves and their families before and during disasters and other emergencies," FCC Chairman Kevin Martin said following approval of the plan．
Participation in the alert system by carriers -telecommunications companies is voluntary, but it has received solid support from the wireless industry．The program would be optional for cell phone users．They also may not be charged for receiving alerts．
There would be three different types of messages, according to the rules．The first would be a national alert from the president, likely involving a terrorist attack or a nationwide disease．The second would involve "approaching threats," which could include natural disasters like hurricanes or storms or even university shootings．The third would be reserved for child kidnapping emergencies．The service could be in place by 2010．
1．What is the purpose of the approved plan?
A．To warn people of emergencies through messages．
B．To popularize the use of cell phones．
C．To estimate the monthly number of messages．
D．To promote the wireless industry．
2．According to the passage, cell phone users ____．
A．must accept the alert service． B．may enjoy the alert service for free．
C．must send the alerts to others D．may choose the types of messages
3．An alert message will NOT be sent if____．
A．a child gets robbed in the street B．a university shooting happens
C．a natural disaster happens D．a terrorist attack occurs
4．Which of the following can be the best title for the text?
A．Cell Phone Alerts Protecting Students
B．Cell Phone Alerts by Wireless Industry
C．Cell Phone Alerts of National Disasters
D．Cell Phone Alerts Coming Soon