2014年6月英语四级作文真题附范文(第2套):A Beautiful City in China

语句间的衔接成分用的不错，同时文章中的过程性词汇很丰富；作者句法基础较为扎实；作者高级词汇使用比较准确，词汇表达较丰富，但仍需增加词汇积累。

Both the conversion of SO and the selectivity to SC significantly increased with prolonging the reaction time till the reaction time reached 1 h (entries 1–3), as demonstrated in Table 6. As a result, the yield of SC was correspondingly enhanced from 43.3 to 87.5% when the reaction time was prolonged from 0.25 to 1 h. The raise in the selectivity with shorter reaction time reveals that there is a possible induction time at the early stage due to initial low temperature below desired temperature, in which the side reactions are possibly easier to occur. Almost no obvious influence can be then observed with further increasing reaction time, indicating the reaction nearly reached equilibrium around 1 h.