题目

—What is the man, do you know?        —I don’t know exactly. But I think he can be         but a teacher.        A．anybody   B．something C．anything   D．everybody 答案：C（8分）在下列四个核反应方程中，x1、x2、x3和x4各代表某种粒子，①            ②③                      ④①x1是    ②x2是      ③x3是     ④x4是