题目

- _______ your classmates all nice to you?- Yes, ________. A . Do, they do B . Are, they're C . Are, they are D . Is, he is 答案：C在脊蛙反射实验中，要剪去蛙的头部，这一步骤的作用是 [　　] A．便于钩住蛙的下颌B．使蛙停止活动 C．排除脑对脊髓的控制D．为了杀死蛙