请你利用小亮的发现解决下列问题：

下列关于种群和群落的描述正确的是（  ）

朝鲜战争中，苏联选择了旁观；柏林墙危机中，美国保持了冷静；古巴导弹危机中，苏联做出了退让。这反映出美苏（    ）

鲁尔区形成于19世纪中叶，被称为“德国工业的心脏”。位于德国西部、莱茵河下游支流鲁尔河与利珀河之间的地区，区内……工厂林立，城市栉比、人口稠密……是德国和西欧地区乃至世界的重要工业区。结合下图，图中序号表示杜伊斯堡的是(　　)

阅读理解

    Mary is a very little girl. She is only three years old. She can't read and write, but she likes drawing very much.

    One day, her sister, Jean sees her at the desk. She thinks Mary is drawing. She comes to her, but she finds Mary isn’t drawing. She is writing on the paper.

“What are you doing, Mary?” Jean asks her.

“I’m writing to Ann. ” She answers.

“But you don’t know how to write, how can you write to her?”

“Oh, it doesn’t matter(没关系). Ann can’t read and write, either(也). ”