染色体是细胞内遗传物质的主要载体．下图为细胞内染色体的组成关系图解．请据图回答问题：

（1）生物体内a的种类约有____ 　种，其结构通式为　____  ．A是由a经____  反应形成的，形成肽键的结构简式是____ ．

（2）细胞中b的种类有____  种，分子中____  不同，决定了b的种类不同．B主要分布在____ 内．

    Hello, Listeners. Welcome to Henton Hospital Radio. Before our music program at four, I'm going to repeat some of our hospital rules.

    The hospital can sleep 800 patients. There're 8 beds in each ward (病房). The visiting hours are in the afternoon from 2:30 to 3:30 and in the evening from 7:00 to 8:00. But remember only two people can see you at the same time. Sorry about that, but you can see what would happen if we didn't have these rules.

    The other rules are about our hours. We start quite early---you might not be used to that. We wake you at 6 o'clock, and breakfast is at 8 o'clock, lunch is at noon.

    There's tea at 3:30 and supper is at 6 o'clock.

    You can see the non-smoking sign –-- we don't allow smoking in the wards. I'm sure you understand why. However, if you do need to smoke, there are some smoking rooms where it is allowed.

    You will find the radio switch (开关) on the wall near your bed, with your own headphones, if you want to listen. It's our own hospital radio wishing you a quick recovery (康复).

下列各句中，没有错别字的一项是 （        ）

作文：

      心愿像一粒种子，播种在心的土壤里，尽管它渺小，却可以开出最美的花朵。心愿，像一条小溪，流淌在爱的大地上，尽管它涓细，却可以浇灌绿色的希望。

      请以“心愿”为题写一篇记叙文，可以是关于自己的，也可以是关于亲人的、朋友的故事。

      要求：①根据写作的内容和表达的中心，合理安排文章的详略和描写方法；②关注记叙中的议论和抒情；③不得套做和抄袭；④字数不少于600字。