Last month, Justin Valdez, a college student, was shot in a subway station in San Francisco. The surveillance video(监控录像) showed that before Justin was killed, the killer pulled out his gun several times, and even wiped his nose with it. However, nobody noticed the killer. The surrounding passengers all focused on their cell phones.
We may see the same scene everywhere in our life: in subway stations, restaurants, elevators and so on, people are watching their cell phones. From a family reunion to a date with a friend, people couldn’t stop checking their twitter and facebook on the cell phones and ignoring the persons in front completely, Phubbing(低头症) not only involves young people, but also the elderly and kids.
“Phubbing” is a new term which comes from the words “phone’’ and “snub(冷落)”. It describes the habit of snubbing someone in favor of a cell phone. The word “phubbing” was included in the Australian National Dictionary in 2012. Obviously, the indifference（冷漠) and rudeness of the information age are spreading globally. A Stop Phubbing campaign website has been set up. You can find the slogan of the website as follows: “stop twittering, stop posting photos…enjoy your food, enjoy the music and respect others.”
Phubbing appears harmless. However, it does influence our life. Jimmy, an epicure(美食家), wrote in his blog: “I can no longer focus on what I am eating since I started twittering. My skill of food photography has improved very fast, while my interest in food drops as a result.”
Let us put down our cell phones and re-enjoy the real taste of our food and the warmth of 
interpersonal communication.
29.The case of Justin Valdez is given in the first paragraph to show .
A. gun violence happens easily in the US B. the killer had made a careful plan
C. the killer didn’t mean to kill him D. phubbing may lead to terrible disasters
30.Jimmy’s words suggest that .
A. phubbing is actually harmless
B. phubbing affects people’s eating habits the most
C. phubbing stops people enjoying their life
D. phubbing helps people improve their photographic skills
31.What is the text mainly about?
A. How the word “phubbing” came into being.
B. The popular campaign of stop phubbing.
C. The great harm of phubbing
D. The meaning of the word “phubbing”.