下列图形中，不是中心对称图形的是（）

A. key opinion Leader
B. knock out Leader
C. key opinion consumer
D. key of content

A. IETF
B. IRTF
C. ICANN
D. internet society

A. 7
B. 6

A. cknowledge, Catch Phrase, Question认同、呈现价值、提问
B. Acknowledge, Check, Question认同、确认、提问
C. Attention, Clarify, Question关注、澄清、提问
D. Attention, Close, Question关注、结束、提问