一 Excuse me, may I come in?
一 Not yet. Please wait on your chair your name is called.
A:and
B:until
C:after
D:since
“鱼浮灵”主要成分是过碳酸钠(xNa2CO3•yH2O2),俗称固体双氧水.兴趣小组对其进行以下探究:
已知点P(m,n)在第四象限,则直线y=nx+m图象大致是下列的( )