閱讀理解。
   If you look at the top of your phone，you'll usually see a little symbol that says 3 G or 4 G.The "G" stands for the "generation" of your mobile network.But these symbols will become things of the past after 5 G networks fully arrive.
   On March 30th，2019，Shanghai vice-mayor（副市長(zhǎng)）Wu Qing made the first 5 G video call on a Huawei Mate X smart phone，CGTN reported.Shanghai has also become the first city in China to start testing 5 G metworks.
   About 100 times faster than 4 G networks.5 G will let people download and upload data faster than ever before.But 5 G won't just bring faster mobile Internet.People can use it for many other things as well.
   For example，5 G will help to make self-driving cars safer.Today's self-driving test cars have one problem lag.When the car "sees" an obstacle（障礙物），it sends the information to a data center and receives instructions.However，it takes time to send and receive information.With this kind of lag，the cars might crash because they don't receive instructions in time.With 5 G，this lag will be great lowered ，making the cars safer，according to CNN.
   5 G could also be used to power the Internet of Things（IoT 物聯(lián)網(wǎng)）.This refers to a large online network that connects all things and people.Fast Internet speeds will be the key to develop this technology.
The IoT could be used in a lot of ways.For example，with IoT，your refrigerator could automatically（自動(dòng)地）place an order online for eggs when it finds that there are no eggs left inside.
（1）We can know from the passage that 5 G

C

C

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A．has been firstly tested in Beijing
B．stands for the generation of your smart phone
C．can make the networks 100 times faster than 4 G
D．will be fully used immediately
（2）The writer uses self-driving cars as an example to

A

A

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A．explain how 5 G's fast speed can be helpful
B．explain how self-driving cars work
C．show us how advanced self-driving cars are
D．warn about the possible dangers of self-driving cars
（3）According to the passage，the IoT is

C

C

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A．a(chǎn) robot that can do housework
B．a(chǎn)n online store where you can buy anything
C．a(chǎn) large online network that connects things and people
D．a(chǎn) type of high-tech refrigerator