我期中考试刚写的英语作文,请线上老师帮忙评分（满分25）,并作修改,

我期中考试刚写的英语作文,请线上老师帮忙评分（满分25）,并作修改,
假设你是星光中学的李华,将参加主题为“let’s ride bicycles”的英语演讲比赛.写一份演讲稿,主要内容包括：1.目前汽车带来的空气污染和交通堵塞等问题.2.骑自行车的益处,如能环保有利健康等.（开头已给出）
Good morning ,everyone,
I am LiHua from Xingguang Middle School.The topic of my speech is "Let's Ride Bicycles".(给出部分)
When it comes to low-carbon life,a majority of people hold various views of it and take different action to support it.As a student,I heartily subscribe to the idea——"Let's Ride Bicycles".
With the rapid development of technology,an increasing number of cars are being produced.Not only has cars brought severe air pollution,but they contribute to more traffic jams as well.But if we use bicycle as our daily transportation tools,the situation might be greatly improved.First and foremost,riding a bicycle is undoubtedly energy-saving and environmental-friendly,thus boosting our sustainable developent.Plus,it's a kind of physical exercise ,which does massive good to our health.What's more,we're inspired to develop a merit of being economical by riding bikes.
On the whole,riding a bicycle does benefit us alot.And only through our joint efforts,such as riding a bicycle,can we human beings live in harmony with nature.
大抵是这样的,但我把sustainable拼成了substainable,会扣几分?

一般都是扣3分左右
我来评我会给23分
再问： 能否做下修改
再答： Good morning,everyone, I am Li Hua from Xingguang Middle School. The topic of my speech is "Let's Ride Bicycles".As is known to us, air pollution and heavy urban traffic are becoming increasingly severe mainly due to the overuse of cars. Therefore, it’s high time we chose another better means of transport, that is, cycling. There are many good reasons to ride bicycles. First of all, compared to cars, bicycles are much cheaper to buy and maintain, and you don't have all the added costs of fuel, and parking. What's more, bicycles are more environmentally friendly than cars, because they hardly make noises and exhaust. Cycling has become a new trend around the world, a good way of energy saving and low-carbon life. Last but not least, cycling is an excellent way to keep fit and live longer. By riding bicycles, you can cut down your risk of heart attacks, high blood pressure and other illnesses. So I think, riding bicycles actually has great effects on us. Let's ride bicycles from today on! Thank you for listening!