曲线y=x3在点（1，1）处的切线与x轴、直线x=2所围成的三角形的面积为（ ）
如图所示的电路中，电源电压不变，R1为定值电阻，开关S闭合后，滑动变阻器滑片P向右移动时，下列说法正确的是（ ）
— Did you listen to the program yesterday?
— Yes. I can't believe I heard her singing ______ the radio.
Not only ____ he speak English correctly, but ____ he speaks it fluently.
CO(g)+H2(g), CO(g)+H2O(g) 