要检验某溴乙烷中的溴元素,正确的实验方法是( )
A:加入溴水振荡,观察水层是否有棕红色出现
B:滴入AgNO3溶液,再加入稀硝酸呈酸性,观察有无浅黄色沉淀生成
C:加入NaOH溶液共热,然后加入稀硝酸呈酸性,再滴入AgNO3溶液,观察有无浅黄色沉淀生成
D:加入NaOH溶液共热,冷却后滴入AgNO3溶液,观察有无浅黄色沉淀生成
设0≤x<2π,且1-sin2x=sinx﹣cosx,则( )
____ a new ____.
—Nero is crying. Do you know _______ she's so upset?
—Well, she lost her pet cat which was just like her family member.