弹簧测力计下挂着一个重15N的物体，手同时用一个竖直向上的力托住这个物体，此时弹簧测力计的示数是10N，则手对物体向上力的大小是（ ）
A：10N
B：5N
C：0N
D：15N
It's not proper for kids to have too much pocket money because they may buy ______.
— ____ (who) is that dress?
— Isn't it ____ (you)?
— Oh, yes. It's mine.
