气相色谱仪中的流动相是（）。
A.液相
B.气相
C.气液混合相
D.固相
参考答案：B
Helen had to shout ________ above the sound of the music. [ ]
A. making herself hear
B. to make herself hear
C. making herself heard
D. to make herself heard
991×0.001+991×0.999：( )。
A．99.1
B．991
C．9910
D．9.91
