—Before he went on the stage,he took a deep ______ .
—He was too nervous.
A:breath
B:smile
C:voice
思考:a2a是分式还是整式?小明是这样想的:因为a2a=a2÷a=a,而a是一个整式,所以a2a是一个整式,你认为小明的想法正确吗?
下列计算,一定正确的是( )
若sinA=23,则A的取值范围是( )