判断题 红茶宜沸水冲泡，常选用白瓷杯为宜，以便鉴茶观色。（  ） 正确 错误

单项选择题 The Declaration of Independence include the following contents except A、natural rights to life, liberty and the pursuit of happiness B、government under social contract C、accusation of power abuse of the British King D、institution of a new government system

单项选择题 下列化合物按SN1历程反应的活性由大到小为（ ）