①w= $\frac{36.5c}{1000\rho }$ ×100%　  ②c=1mol•L^﹣1　  ③向上述溶液中再加入V mL水后，所得溶液的质量分数大于0.5w　  ④所得溶液中含有N_A个HCl分子．

小明和小李、小凯三人读同篇朗读稿，小明用了$\frac{2}{15}$小时，小李用了$\frac{1}{6}$小时，小凯用了$\frac{3}{10}$​小时，谁读得最快？（　　　　）

两个数都是质数，这两个数一定是互质数．

阅读理解

    My name is Sun Liang．Li Feng is my cousin．He is thirteen years old and I'm twelve years old．We study in the same school but not in the same grade．He is in Grade 8 and I'm in Grade 7．

    Li Feng is tall and strong．He plays basketball well．He thinks it's a good way to stay healthy．So he often plays basketball with his classmates in the playground．He likes collecting the pictures of famous basketball players．Last Sunday,he watched a basketball match．He was happy because he saw his favourite basketball star．

    I also like playing sports but music is my favourite．I think it's a good way to relax after a busy day．My father is a music teacher and he is good at playing the piano．So I learn from him to play the piano．It was my birthday yesterday．I had a party and I was happy．

根据材料内容选择最佳答案。

以下各项最能说明新航路开辟对世界历史发展起到积极作用的是（    ）