Teenagers should mind their manners when traveling on a bus or train. They will be told to "stand up for their elders" on public transport -or may lose their right to free travel.

　　Officials in London will declare plans lately to make youngsters sign a "courtesy pledge" to promise to behave in a respectful manner when travelling in the capital. The three-point pledge states that they will give up their seats to the elderly, pregnant and disabled; keep from using offensive or threatening language; and be courteous and polite to fellow passengers and staff.

　　The teenagers who refuse, or are caught behaving in a loutish manner, will have their free travel passes removed. The plan will initially affect the 400,000 11-to-15-year-olds in London who qualify for free travel cards.

　　During an interview, a Conservative insider said: "The plan corresponds perfectly with the push to create a Big Society. It is about changing culture and expectations around behavior on buses and trains for everyone."

　　Mr. Johnson said he was determined to deal with the anti-social behavior of a "minority of youngsters" on public transport. "When I was a boy, I was taught to stand up for those less able to, " he said, "Youngsters enjoy the privilege of free travel, which is paid for by Londoners, but they have to understand that with that privilege comes responsibility. Anyone who abuses this privilege will have it taken away, and will have to earn that right back."

　　Teenagers found guilty of a serious violation (违背) of the new behavior rules will lose their travel passes, and will have to carry out unpaid community work to earn them back.

　　Mr. Johnson is also introducing a "two strikes and you're out" policy to deal with repeated offenders, under which those committing a second serious violation of the rules will lose their free travel rights permanently

21. Which is NOT included in the "courtesy pledge"?

A. To offer their seats to those in need.

B. To stop using aggressive language on public transport.

C. To show courtesy and politeness to people on board.

D. To avoid bothering others by talking too much.

22. What's the purpose of carrying out such a plan?

A. To prevent those rule-violators having their free travel rights.

B. To help create a harmonious atmosphere on public transport.

C. To deal with the anti-social behaviors of most youngsters.

D. To encourage teenagers to take part in unpaid community work.

23. Which is the most severe punishment to rule-violators?

A. They will be forbidden to take public transport.

B. They will have to do unpaid community work.