A:商品经济发展冲击传统观念
B:晋商经营理念先进
C:资本主义萌芽产生并缓慢发展
D:科举制度已经衰落
A:Hi, Li Ming.
B:Hi, Mrs Li.
A:What are you doing?
B:I'm reading a story book. What are you doing?
A:I'm writing a letter. May I look at your story book?
B:Certainly. Here you are.
A:Thank you.
实验次数
斜面倾斜程度
物体重G/N
斜面高度h/m
沿斜面拉力F/N
斜面长s/m
有用功W有/J
总功W总/J
斜面的机械效率η
1
较缓
5
0.1
1.5
0.5
33.3%
2
较陡
0.2
50%
3
10
4
最陡
0.3
2.4
62.5%
动物的身体结构总是与其功能相适应.根据这一生物学基本观点,分析回答下列问题.