12个月的婴儿，锌的参考摄入量为（）mg。
A.15.0
B.10.0
C.9.0
D.8.0
参考答案：C
He ___ without saying good-bye to them, for he always has good manners.
A．mustn’t have left
B．may not have left
C．shouldn’t have left
D．can’t have left
心理测验法
