4472-38×72=( )
A:1204
B:1736
C:1584
D:1636
——I hear you______ in a sports center. What's it like?——Well, it's very hard work and I'm always tired, but I don't mind.
如图所示为一正弦交流电电压随时间变化的图像,下列表达式正确的是( )
等式xx-3=xx-3 成立的条件是( )