托福Toefl作文模拟题附范文 第42篇:21世纪的到来会产生怎样的变化

作者词汇基本功很好，一些高级词汇的使用也比较灵活；可将文中的简单句转换为长句或者复杂句；文章结构不够严谨，应增加过程性词汇的使用。

Dear Prof. Chung Chieh, This is Wenhua Zuo from China. Today, I visited your chemistry website and have learned very useful information about hydration energy. Your website is amazing and helped me a lot. But I still need some help; 1. The values of Enthalpy of Hydration of some ions on your web are ten times higher than values presented in the book "supercapacitors" (2011, ISBN:978-3-527-32869-7 P10) which edited by Francois Beguin and Elzbieta Frackowiak. I want to know if this differential is acceptable. 2. The hydration energy values of your website were used by Prof. S. Bandarenka (Energy Environ. Sci., 2016, 9, 955). And if I want to use these values, could you tell me how to cite and tell others where these information comes from? 3. My research interests are aqueous batteries and supercapacitors. In the last year, we found an interesting material which has reversible redox activity in various electrolytes thus make it a versatile electrode material for many kinds of metal ion batteries. And we found that the cathodic/anodic peak position of this material is related to the ions in each solution. Specifically, the smaller hydration energy of cation, the more negative redox potential. Here are the last two questions: a. could you please provide me the hydration energy values of another two anions (SO42- and NO3-)? It is hard to ask you but I have tried to find them by myself over a week and all my efforts were in vain. b. We have found the specific link between enthalpy of hydration and redox potential accidentally. You are expert in chemistry. In your perspective, is this connection sound and what other factors influence the redox potential of one material in aqueous electrolytes? I am so sorry to interrupt you and I hope you can spare your time to solve my puzzles. Thanks a lot. yours sincerely. Wenhua