李嘉图的比较成本学说尽管比斯密的绝对成本学说有进步的发展,但是也有难以克服的局限性,其局限性表现在( )
①对一国参与国际分工的危险性估计不足
②反映了当时英国资产阶级向外扩张、建立世界霸权的愿望
③反映了不同国家间经济发展的一种内在联系和客观要求
④认为生产相同的产品,不同国家的成本不一样
A:①②
B:③④
C:①③
D:②④
现在体积为1L的密闭容器中,充入CO2和H2.实验测得反应体系中物质的物质的量与时间关系如下表,
n(CO2)
n(H2)
n(CH3OH(g)
n(H2O(g)
0
1.00mol
3.25mol
0.00
5min
0.50mol
10min
0.25mol
0.75mol
15min
n1
回答下列问题:
从所给出的单词中选出合适的完成对话。
swim ride cousin What is
Tom: Hello, Peter. Who is that boy?
Peter: He is my____. He is my uncle's son.
Tom: What____ his name?
Peter: His name is Jim.
Tom: Can he____?
Peter: Yes, he can. He likes swimming.
Tom: Good! I like it, too.____about you?
Peter: No, I can't swim. But I can ____a bike.
如图1,△ABC是等腰直角三角形,∠BAC=90°,AB=AC,四边形ADEF是正方形,点B、C分别在边AD、AF上,此时BD=CF,BD⊥CF成立.
马可波罗来到中国时,中国处于( )