与二氢黄酮反应后产生天蓝色荧光的是
A.HC1-Mg反应
B.NaBH4反应
C.MgAc2反应
D.SrC2/NH3反应
E.FeCl3反应
参考答案:C
I ________ on a sofa because my grandparents have been here for the weekend. [ ]
A . slept
B. was sleeping
C. have slept
D. am sleeping
按周期分,失眠可分为?()
A.短暂性失眠
B.短期性失眠
C.长期失眠
D.彻夜不眠