为什么Our class have 要用have,而不是has?为什么at some agreement要用any?

为什么Our class have 要用have,而不是has?为什么at some agreement要用any?
短文改错题目Our class have had a discussing recently on whether it is necessary to start learning English from childhood. Some for it. As little boys and girls have had a very good memory, they can learn a lot of English words by heart very easy. This will help their future English learning. While others don’t agree. They think children have to learning Chinese pinyin at school. If they study Chinese pinyin and English at same time, it will be very easy for them to mix it up. This will do a lot of harm to their Chinese learning and their future English learning. For short, we have not arrived at some agreement yet.答案：Our class have had a discussion recently on whether it is necessary to start learning English from childhood. Some are for it. As little boys and girls have a very good memory, they can learn a lot of English words by heart very easily. This will help them in their future English learning. While others don’t agree. They think children have to learn Chinese pinyin at school. If they study Chinese pinyin and English at the same time, it will be very easy for them to mix them up. This will do great harm to their Chinese learning and their future English learning. For short, we have not arrived at some agreement yet.

这里的our class指的是班级的每一个同学,如果指班级这个整体,就要用单数.
因为at some agreement所在的句子是一句否定句,在否定句或疑问句中表示“一些”或者“任何”、“某个”,要用any来表示.希望我能帮助你解疑释惑.