幼年时生长激素分泌不足会导致

    A 12-year-old boy got lost on the subway after going out alone on Sunday. The boy came to Shanghai to visit his parents during the summer holiday. Although his parents were happy to see him, they ____ little time with him. The boy did his homework for two ____ and felt bored, so he went out to play on the subway. He had fun playing there. But when he felt tired and hungry, and wanted to go home, he didn't know at which station he should get off. The police found the boy ____ on the subway and took him to the office. They bought him something to eat and asked him some questions. The boy's parents couldn't find him after arriving home. They felt ____ and called the police right away. They got to the police office and saw ____ son. They were very happy and thanked the police.

下列表示人体内气体交换的过程，其中能发生气体交换的是（　　）

空气 呼吸道 肺泡 血液 组织细胞．

对于如何建设社会主义，列宁曾说：“增加财富、建立社会主义社会的真正和唯一的基础只有一个，这就是大工业。如果没有资本主义的大工厂，没有高度发达的大工业，那就根本谈不上社会主义，而对于一个农民国家来说更谈不上社会主义了。”这一思想（    ）