2010年8月，圣元奶粉因含有性激素造成儿童性早熟而遭到卫生部审查．下列有关性激素的说法，你不认同的是（　　）

如图所示，用细线吊着一个质量为m的小球，使小球在水平面内做圆锥摆运动，关于小球受力，正确的是（   ）

下列事实中，一般不能用于判断金属性强弱的是(　　)

A —— salesgirl         B —— customer
A: Good afternoon, can I help you?
B: Yes, ____ 
A: We have different kinds of sports shoes. They’re all in style. What color would you like?
B: I prefer blue.
A: ____ ?
B: Size 40.
A: What do you think of this pair?
B: Great! ____  ?
A: Certainly. This way, please.
B: Oh, they fit me very well. ____ ?
A: 500 Yuan.
B: ____ . I can't afford.
A: Well, I'll give you a 20% discount.
B: OK. I'll take them.