下列叙述中，与长骨结构坚而不重特点无关的是（　　）

阅读课文片段，完成练习。

      一天，贾岛去长安城郊外拜访一个叫李凝的朋友。他沿着山路找了好久，才摸到李凝的家。这时，夜深人静，月光皎洁，他的敲门声惊醒了树上沉睡的小鸟。不巧，这天李凝不在家，贾岛就把一首《题李凝幽居》的诗留了下来。 第二天，贾岛独自骑着毛驴返回长安。半路上，他想起昨夜即兴写成的那首小诗，觉得“鸟宿池边树，僧推月下门”中的“推”字用得不够妥帖，或许改用“敲”字 更恰当些。贾岛骑着毛驴，一边吟哦，一边做着敲门、推门的动作，不知不觉进了长安城。大街上的人看到他这个样子，都感到十分好笑。 这时，正在京城做官的韩愈，在仪仗队的簇拥下迎面而来。行人、车辆都纷纷避让，贾岛骑在毛驴上比比划划，竟然闯进了仪仗队中。

                                B     

    Hippos(河马) live in Africa(非洲). They are one of the world's largest land animals. Here are some interesting facts about them.

●Where are hippos born?

    Hippos often give birth in the water. The hippo babies get out of water right after birth to take their first breath.

●How quickly do hippos grow up?

    Hippo babies nurse both under water and on land for a year. Then they stop taking their mothers' milk but they are still with their mothers until they are eight years old. Then they move out.

●What do hippos love?

    Hippos love water and they spend most of the day in it to stay cool. The Hippo can breathe, see and hear when its body is under water because its nose, eyes and ears are on the top of its head.

●Do hippos swim better than people?

    Yes, they are great swimmers and they can hold(屏住) their breath for five minutes. Hippos can even walk under water along the bottom(水底) of rivers and lakes.