统计分析，目前共有（）种故障率曲线.
A.一
B.三
C.五
D.六
参考答案：D
跳跃反应的中枢位于（）。
A．脊髓
B．延髓
C．脑桥
D．大脑皮层
Most schools of the Communicative Approach share the view that language is used for communication, and they are primarily concerned with the ______ rather than the structure.
A. communication B. meaningC. interaction D. participants
