How to remember vocabulary

Today I listened to the Xiaolai's IBT lesson on duobei.com. The following is what I thought.

I think this web platform is very useful for future teaching, because this platform can make teaching and learning online more easy. Although I don't know how the web make its money to survive.

To teach in such a platform, teacher meet a great challenge than normal class. Because you can't control students in online classroom, they can come and go as they like, and they also enjoy more freedom and say anything as they like. In order to solve this problem, teachers may selectively to response to students' answer.

The writing test is very humanistic. It would give you full score if your essay largely accomplish all of the following conditions. And the subjects is open to all test participants.

group number:139127868

ichthyosaur 水龙
pterosaur    翼龙