选出恰当的应答语( )
A:Sure,hold on please.
B:Thank you.
C:I'm speaking to you.
My father ________ lots of stamps since he was at primary school.
如图是初中化学中常见仪器装置,回答下列问题:
如图,将透明三角形纸片PAB的直角顶点P落在第四象限,顶点A、B分别落在反比例函数y= kx 图象的两支上,且PB⊥x于点C,PA⊥y于点D,AB分别与x轴,y轴相交于点E、F.已知B(1,3).
下列现象中,不是属于光的直线传播的是: ( )
美洲的东面和西面分别临: