第二段：the sea level will rise...
While doing shopping,we are supposed to use green bags.What's more,while travelling,we had better take a bus,ride a bicycle or walk to our destination.
第三段：...handwriting held in our ...
...it is also a way to save the world.
Saving the world is everyone's duty.
其他都很棒~有很多高级词汇和句式.祝演讲成功!