简述无线信号收发时主要步骤。

男女生不许拥抱、牵手、搂腰，不许互相喂饭，不许单独面对面吃饭，不许单独相处……日前，浙江台州的路桥金清中学推出了男女生交往过密的8项“判定细则”，一旦有学生违反，学校将依据规定给予严肃处理。该校的做法

A．其出发点是好的，但不利于男女生的正常交往

B．是正确的，这是专家们集体研究成果的结晶

C．是切实可行的，也是被实践充分证明了的，具有很强的操作性

D．这个标准，用于一部分人很好，加于全体同学，也是切实可行的。

阅读理解。

     "Our aim is to take our art to the world and make people understand what it is to move," said David

Belle, the founder of parkour(跑酷)．

     Do you love running? It is a good exercise, yet many people find it boring. But what if making your

morning jog a creative one? Like jumping from walls and over gaps, and ground rolls? Just like the James Bond in the movie Casino Royale? Bond jumps down from a roof to a windowsill and then runs several

blocks over obstacles on the way. It is just because of Bond's wonderful performances that the sport has

become popular worldwide.

     Yes, that's parkour, an extreme street sport aimed at moving from one point to another as quickly as

possible, getting over all the obstacles in the path using only the abilities of the human body. Parkour is

considered an extreme sport. As its participants dash around a city, they may jump over fences, run up

walls and even move from rooftop to rooftop.

     Parkour can be just as exciting and charming as it sounds, but its participants see parkour much more

than that.

     Overcoming all the obstacles on the course and in life is part of the philosophy(理念)behind parkour.

This is the same as life. You must determine your destination, go straight, jump over all the barriers as if in parkour and never fall back from them in your life to reach the destination successfully. A parkour lover

said, "I love parkour because its philosophy has become my life, my way to do everything."

     Another philosophy we've learnt from parkour is freedom. It can be done by anyone, at any time,

anywhere in the world. It is a kind of expression of trust in yourself. It is only a state of mind. It is when

you trust yourself that you earn energy.

1．Parkour has become popular throughout the world because of ________.

A．its founder, David Belle

B．the film, Casino Royale

C．its risks and tricks

D．the varieties of participants

2．The underlined word "obstacles" in Paragraph 2 is closest in meaning to "________"．

A．streets  

B．objects  

C．barriers  

D．roofs

3．Which of the following is true of parkour?

A．It challenges human abilities.

B．It is a good but boring sport.

C．It needs special training.

D．It is a team sport.

4．As its participants move around a city, ________.

A．they can ask for help

B．they may choose to escape

C．they should run to extremes

D．they must learn to survive

当变电所的一条供电线路出现故障造成一台局扇停运时，另一条供电线路能保证另外一台局扇正常运转，从而保证用风地点通风的（）

A、间断性

B、其它性

C、连续性

已知某投资项目的项目计算期为5年，资金于建设起点一次投入，当年完工并投产，投产每年净现金流量相等，预计该项目包括建设期的静态投资回收期为1.6年，则按内部收益率确定的年金现值系数是3.4。 ( )