434. To sum up, given all the reasons discussed above, we can safely reach the conclusion that the earth is being harmed by human activity.
總之，通過以上討論的種種原因，我們可以得出這樣的結論：地球正在由于人類的活動而遭到破壞。

六級詞匯講解:
本句是建議型的結尾段落。To sum up一般是結尾段的信號詞，表示總結，也可以使用In summary、To summarize、In sum、In brief、In short、In a word、In a nutshell、All in all、Generally speaking等表示結論。we can safely reach the conclusion that...后接同位語從句，陳述作者的結論。

句型拓展:
In conclusion, I believe that it's better to be a leader of a group rather than an ordinary member.
總之，我認為做一個團隊的領導者要比做普通成員更好。
In summation, I much prefer classes where the students do some of the talking.
總之，我喜歡部分時間由學生發言的上課方式。
My conclusion is that the best way to develop one's skill is to put theoretical knowledge to practical use in the real world.
我的結論是，培養一個人的技能的最佳途徑就是將理論知識運用于實踐。
I can draw the conclusion that universities should not, and do not need to, spend the same amount on their sports activities as on their libraries.
總之，各高校不應當、也不必在體育設施上投入像圖書館那樣多的資金。