Useful websites for learning coding
（1）code academy
（2）OSS University：Path to a free self-taught education in Computer Science!
https://ossu.firebaseapp.com/#/
（3）Coding online
(4)Javascript advanced
(5)opensource code platform
(6)Child coding
http://appinventor.mit.edu/explore/
(7)
将github地址映射为可运行的py notebook: https://mybinder.org/
NLU open API and platform
(1)facebook NLU API
(2)google NLU API
(3)MS NLU API
Teaching assistant:
https://www.socrative.com/