Our world is facing unprecedented crises in history: climate change, Covid-19 pandemic, social injustice, and so forth. While some might say these problems are impossible to solve, I would be confident of humankind’s capacity and optimistic about our world’s future. I honestly believe I could see those problems solved during my lifetime.

Throughout history, human beings have confronted numerous challenges from the Stone Age to the Third Technology Revolution. Our ancestors living in the remote caves in Africa were dealing with the risk of predators like lions and tigers every single day. Several hundreds of years later, we became the paramount species through teamwork, wisdom, and perseverance. After nuclear weapons invented, many were afraid of the outbreak of nuclear war. Because it was estimated once it broke out, the whole amount of dusts released by the explosion of nuclear weapons would block the sunlight and bring about the longest winter in human history. One hundred years later, even though there were tensions between empires like the USA and the Soviet Union, we only saw the Cold War instead of the Nuclear War. Lots of international agreements on nuclear weapon usages have been signed between countries, aiming to reduce the quantity of nuclear weapons gradually down to zero. Those successful instances above displays how smart we humankinds are and comfort our anxiety of the future.

It is true we are confronting severe crisis now and the very few is treating them serously. However, I believe as long as we see the consequences such as possible extinction, the whole world would definitely work together to solve them, for no one can risk the cost of its life.

To sum up, I believe in human efforts and wisdom. The long history has repeatedly proven it. Each generation has its own crises to face, and it turned out we have done great so far. Therefore, I would say proudly and confidently, problems in front of us are bound to be solved during my lifetime. And I look forward to that.

老师已经修改好，最后几段您给我的截图里没有，我凭感觉改的。

想问一下，definitely 和 because, everyday， difficult 为什么要替换，是因为low了嘛