Hi Fu!
Always good to see teachers looking for new ways to help their students learn better.
My family are members of an online e-learning club called Ladder 100 Digital Education. It is also used by many education centers around Taiwan, as well as other countries in Asia, esp. China and Singapore.
This is a whole-family kind of thing, as it has tons of stuff, for young kids, teenagers and adults, too.
Not only English, but online software for all school subjects that matches up with government standards from Grade 1 up thru high school.
There are also adult-level courses, including online GEPT, live online voice chat with American teachers, Japanese, French…
There’s also a lot of really good interactive software for both Chinese and foreigners to learn Mandarin, from the most basic level all the way up to getting ready for the college entrance exams.
Honestly, there is too much stuff to list, you really have to see for yourself.
However, you need to be a member to access the site. 
Warning! This is an MLM business. If you are allergic to MLMs, pls. consult your doctor b4 proceeding to study. 
Anyway, there’s my 2 cents and then some.
If your student’s family joined, we would be glad to give you a commission on the deal.
Any questions, pls. feel free to PM me.
Regards,
James
