I want to join the Music society, because I like playing the _________.[ ]
A.
B.
C.
答案:A
若n为正整数,且x2n=3 ,则(3x3n)2-4 (x2)2n的值为 [ ]
(A)207
(B)36
(C)45
(D)217
ICD-10关于轻躁狂发作的诊断标准对于症状持续时间的要求是()
A.至少2周
B.至少5天
C.至少4天
D.至少3天
E.至少1周