题干

三氟化氮(NF3)是微电子工业中一种优良的等离子蚀刻气体。它无色、无臭,在潮湿
的空气中能发生下列反应:3NF3+5H2O=2NO+HNO3+9HF,下列有关说法正确的是

A:反应中NF3是氧化剂,H2O是还原剂

B:反应中被氧化与被还原的原子物质的量之比为2∶1

C:若反应中生成0.2mol HNO3,则反应共转移0.2mol e

D:NF3在潮湿空气中泄漏会产生白雾、红棕色气体等现象

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D

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    Sixteen is a special age in the United States. There's often a special celebration for a girl's 16th birthday---a big party called Sweet-16. It is like a wedding reception(结婚晚宴) in the number of guests and gifts handed out.

    About a month before the party, the girl's family sends out invitations to the guests. They must buy a special present for the birthday girl and the girl guests find good dresses to wear. A sweet-16 present usually costs $40 to $60. This is about $20 more than the usual-cost of a birthday present.

    The party itself is not held at someone's house. The hostess rents(租赁) a reception hall for the event. Food, cake and a DJ are provided. Around 6'clock, guests arrive and meet the birthday girl. Then the girl and her father have a special father-daughter dance. After that, guests dance for about 30 to 45 minutes.

    Then there is the most important part of the Sweet-16 party, the candle-lighting ceremony.

    The sweet-16 hostess stands behind 16 unlit(未点燃的) candles and dedicates(献给) each candle to her friends, family, and anything that she feels is important to her. A lot of crying and hugging goes on at this time.

    Afterwards, people sit and eat. Most guests begin leaving around 11 o'clock.

    This school year, I have been to two Sweet-16s. I am one of the youngest students in my grade (My birthday is in December). I'll have to wait another year before I can have my own special Sweet-16 party. I can't wait for it!