C

    Some children wish to be writers some day. They want to write stories or books for people to read. That's good! It's good to write something for people to read! But they should know that they need to be good readers first before they are really good writers. They should read a lot of books, instead(代替) of watching TV and spending a lot of time playing games when they are free.

    There is more fun in reading, and you want to look for more books to read.

    Before you decide(决定) to be a good writer, you'd better say to yourself, "I must read more and more!"

如图，矩形OABC的顶点A在y轴上，C在x轴上，双曲线y=$\frac{k}{x}$与AB交于点D，与BC交于点E，DF⊥x轴于点F，EG⊥y轴于点G，交DF于点H．若矩形OGHF和矩形HDBE的面积分别是1和2，则k的值为（　　）