题干

核黄素又称为维生素B2,可促进发育和细胞再生,有利于增进视力,减轻眼睛疲劳。核黄素分子的结构如右图:

已知:
有关核黄素的下列说法中,正确的是:

A:该化合物的分子式为C17H22N4O6

B:酸性条件下加热水解,有CO2生成

C:酸性条件下加热水解,所得溶液加碱后无NH3生成

D:不能使酸性高锰酸钾溶液褪色

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答案(点此获取答案解析)

B

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任务型阅读

    Do you have the experience of digging out your suitcase, deciding what to bring and being afraid that you've forgotten something?____ Hope they can transform the way you pack.

    Keep a Basket Handy

    Do you wait until the last minute to pack? Keep a basket in your bedroom, living room, or bath room that you can use to throw in items you'll need to pack as you come across them.____Besides, you can just put the contents of the basket into your suitcase if you are in a hurry to leave for the airport.

Buy Wrinkle-free Clothing

    You won't need to worry about carefully packing your items of clothing if they're made from wrinkle-free materials.____You'll still look fresh and bright when you are in them at your destination.

    Keep Old Packing Lists

    Chances are that you end up taking trips that require you to pack similar items. Keep old packing lists from former vacations to the beach, ski resort, and city—that way, you'll always have a list of at least the basics.____So you don't need to waste your effort to remember where you left your hand-written packing lists.

    Schedule a Packing Time

    Time can slip away from you before a trip-you may be caught up at work, at home, or be occupied with other responsibilities of daily life.____ That way, you will not need to do your packing frantically (狂乱地) from the last minute to 1 o'clock on the day you leave.

A. This makes you less likely to forget the stuff.

B. The best way to do this is to save them on your computer.

C. Buy necessary stuff when you arrive.

D. Determine a night well in advance of departure to pack.

E. That's why I've distilled (提炼) the art of packing down to some essential tips.

F. Just ball them up or put them at the bottom of the suitcase.

G. Rolling your clothes is the best way to save space for the suitcase.