王安是位农学家，如果他要考察长江流域原始农耕文化的相关信息，可以到（    ）

阅读理解(D)
    Sharon's teacher told them that people should protect the environment. But to keep it clean, Sharon had to find it first. After breakfast, she went outside to look.
    Sharon met Herman, a squirrel(松鼠). She asked him about the environment. Herman said, "The environment is everywhere you go. The air you just breathed is part of it. The environment is the air, the water, the soil and our food. It's everything around us." Sharon thought and thought. "I think the Sun isn't part of the environment." But Herman said, "Oh，yes, it is. The sun gives you a vitamin(维他命）you need, Vitamin D. So we should protect the environment. It's important for your life. We can't throw rubbish everywhere. We can't waste things anymore. And we should stop polluting the river. And..."
    Sharon said, " Wow, it's a big job to clean the whole environment. I think I will be busy from now on."

计算机感染病毒后，以下措施中不可能清除病毒的是（   ）

若|a﹣ $\frac{1}{2}$ |+（2b+1）²=0，则a²+b²的值为（   ）

关节是能活动的骨连结,在运动中起支点的作用。如图是关节结构模式图,下列说法正确的是　(　　)