如果单项式﹣x^a+1y³与x²y^b是同类项，那么a、b的值分别为（　　）

①△H（填“＞”、“＜”或“=”）____ 0．

②在一定温度和压强下，若原料气中的NH₃和CO₂的物质的量之比（氨碳比） $\frac{n\left(N{H}_3\right)}{n\left(C{O}_2\right)}=x$ ，如图是氨碳比（x）与CO₂平衡转化率（α%）的关系．α随着x增大而增大的原因是____．

③图中的B点处，NH₃的平衡转化率 为____．

阅读理解。

    This is asong millions of Americans will hear this New Year's Eve. It is called Auld Lang Syne（《友谊天长地久》）. It is the traditional music played during the New Year's celebration. Auld Lang Syne is an old Scottish poem.It tells about the need to remember old friends.

The words "auld langsyne "mean" old long since". No one knows who wrote the poemfirst. However, a version by Scottish poet Robert Bums was published (出版) in 1796. The words and music we know today first appeared in a songbookthree years later.

    The songis played in the United States mainly on New Year's Eve. The version (译文) you are hearing today is by the Washington Saxophone Quartet.

    As we endour program with Auld Lang Syne. I would like to wish all of our radio friendsa very Happy New Year! This is Buddy Thomas.