题目内容：

    As technology in the security field advances, so does the intelligence of the burglars in prevailing over this technology. Gone are the days when a simple alarm system, connected to your phone line, was enough to protect you from potential security risks.

Cellular alarm systems (蜂窝报警系统)are a replacement of the traditional wired phone line security networks. These systems work just like your cell phone. A cellular module is placed in the main control panel and it sends signals, without the use of wires, to the monitoring station. The cellular signal is sent via the data part of a cellular signal, much like a text message.

Sensors can be placed anywhere in your house. Whenever there is an emergency, the relevant sensor picks up the unusual activity and sends a cellular signal to the main control panel. The control panel serves more than one purpose, which sends a cellular signal at the same time to the monitoring service at the back end. The monitoring service later informs the relevant authorities in the form of high-pitched sirens (高音警笛声). Typically it takes a few minutes for emergency services to arrive at the scene. Depending on the efficiency of your monitoring service and the local authorities, help should arrive soon and deal with the potential threats.

It allows you to monitor your house remotely. All you have to do is simply access the cameras from your phone and keep a check for any unusual activities while you are not around. With cellular technology securing your house, you don’t have to worry about the power failure or even burglars cutting your phone lines.

Since these systems operate on batteries, you should be careful about when the batteries die out. There might be other appliances including microwave ovens and WiFi in the house that can cause disruption (干扰). Ensure that your cellular alarm system's range is not affected by the presence of these appliances. Many homeowners tend to go for wireless systems due to the ease of installation (安装）factor. However，keep in mind that a non-professional installation might actually leave the system easy to damage.

1.What do the underlined words ''prevailing over'' mean in Paragraph 1?

A.Improving. B.Defeating.

C.Worrying about. D.Looking into.

2.How can the authorities know an emergency is happening?

A.They hear high-pitched sirens.

B.They read the cellular signal.

C.They check the control panel online.

D.They notice the unusual activity via sensors.

3.What can we know about the cellular alarm system?

A.It looks like a phone. B.It is energy-saving.

C.It needs to be improved. D.It is wireless.

4.What's the purpose of the last paragraph?

A.To give cautions about the system.

B.To introduce the benefits of the system.

C.To call on people to watch out for security risks.

D.To teach people to install the system correctly.