下列哪些特性与SN2反应符合? (1)反应速率只取决于亲核试剂的浓度, (2)亲核试剂从离去基团的反面进攻, (3)反应过程中键的形成和键的破裂同时发生。
A. 1和2
B. 1和3
C. 2和3
D. 全部都是
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你用什么工具答题？
A. 电脑
B. PAD
C. 手机
D. 其它
At present, E-Commerce platforms mainly adopt three types of logistics and they are ( ).
A. enterprise self-support logistics
B. outsourcing logistics
C. Logistics Enterprise Alliance
D. social integrated logistics
The creation of emotional, surprising, funny or unique short videos on TikTok are then shared on WeChat and other channels reflect ________.
A. online community marketing
B. viral marketing
C. microblog marketing
D. social media marketing
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