How to improve khan academy learning system.

We need quizzes mid video to see what we learned so far in the video 
and if we got a certain amount of questions right we can go on or if you got it a certain amount of questions wrong, THEN you watch the whole video, and that will be REALLY helpful.

Edit: I would also like a few staff members and teachers help out the students in an online chat for video call if they really don't get it and, each staff should teach at least 5 students for 20 mins.

Please vote this up so khan academy staffs see this and improve their website!

your best, Salman.O