Mobile phones help us communicate everywhere, which is very impo

Mobile phones help us communicate everywhere, which is very important. They are good .at emergencies, when you've _____（21）a car accident, for instance. A mobile phone_____（22）save your life! Mobile phones are also_____（23）because they have many good features—we can take photos and send them all over the world. But every coin has two sides. The_____（24）thing about mobile phones is that you have no privacy. My boss and friends find me whenever they want! I haven't enjoyed a whole quiet day since the day I_____（25）my mobile phone. _____（26）disadvantage is that mobile phones make us lose good habits, such as punctuality. Before, when we_____（27）keep in touch so easily, if we had a date with someone, we tried our best to arrive_____（28）time. But now, because of the mobile phone, we are not afraid of _____（29）late anymore, so, surprisingly enough, we make people wait! The third,_____（30）I see is that I change my mobile phone once a year, and this means I'm spending_____（31）too much money on it. I think it is important to think_____（32）we use mobile phones. We should use things such as mobile phones, laptops, cameras, the Internet, and so on,_____（33）our needs. We can_____（34）our mobile phone, when we don't want to be disturbed by_____（35）.If we know how to use it, we can eliminate its disadvantages.

34_____.
A、turn off
B、turn on
C、set off
D、set on
【正确答案】：A
【题目解析】：从下文“不希望被打扰”推出应当是“关掉手机”。tum of意为“关掉”；tum on意为“打开”；set off意为“出发”；set on意为“着手做”。