近段时间你发现校园内浪费现象严重，请你在班会上发表演讲，谈谈你所看到的浪费现象及危害，并就这一现象发表个人见解。

One possible version:

Dear friends,

May I have your attention, please? Now I’d like to make a speech here. Nowadays, some of us students have formed some bad habits on campus. For example, some students leave the lights on in the daytime or leave water running after washing. Some leave too much food on the table after eating in the canteen. Besides, waste paper and books can be seen everywhere. So it is high time that we had to deal with the problems.

As is known to all, these bad habits will have bad influence on our character and behavior. What’s worse, they can not only increase our cost at school and add financial burden to our parents, but also waste the limited resources.

If we reduce the waste, we will change the present situation.

That’s all. Thank you!