税收具有调节经济运行，保持经济效率和稳定增长的能力。
参考答案：对
与氢气完全加成后，不可能生成2,2,3-三甲基戊烷的烃是 [ ]
A. HC≡CCH(CH3)C(CH3)3
B. CH2=CHC(CH3)2CH(CH3)2
C. (CH3)3CC(CH3)=CHCH3
D. (CH3)3CCH(CH3)CH=CH2
He ______ short hair. He _________ calm.[ ]
A. is /is
B. has/ has
C. is/ has
D. has/ is
