At first, I need to apologize to you that I maybe  make a lot of grammar mistakes in this comment. Please do forgive me.

Thank you.

Now I am going to tell you why they behaved like this.Besides, as a native Chinese, I am not going to criticise or praise my Country's Education System . I just tell the truth. My attitude is nuetral.

In China, especially when we were children, we were not allowed to discuss questions by ourselves except that we've got the teacher's permission.  If teacher asks us to answer certain questions, we put right hand up if we know the answer exactly. If we don't know or we are not sure our answer is right, we'd better put hand down. Because our  teacher always criticise those who give the wrong answer. So this time being silent will be the best way to avoid being critised. We keep silent and teacher will give us the right answer. Then the class goes on.  I must confess that this habit has been kept for a long time.

In fact, I hate that. But we are trying to change it now. So you're confused of this phenomenon. That's not strange at all. We don't like keeping silent all the time as well. However, the truth is cruel. There's no choice.  I still believe we will change it.

I hope you can understand that these Chinese students didn't mean to behave rudely. They 're just too shy and can't adjust the Britain teaching way at once . Just be patient. And make friends with them . Tell them how to be a real gentleman. hahaha

I hope my answer will help you.