实验室中需要配制2mol/L的NaCl溶液980mL,配制时应选用的容量瓶的规格和称取的NaCl的质量分别是( )
A:980mL 111.2g
B:500mL 117g
C:1 000mL 117g
D:任意规格 111.2g
Which underlined part has a different pronunciation from the others ?
已知函数y=2sinx的定义域为a,b,值域为﹣2,1,则b﹣a的值不可能是( )