Hi Jianlang,

What you generally do in this situation is reference the website in-text and also in your reference list, but make mention of the source of the original quote either in the paragraph before the in-text reference or inside of the in-text reference. 

Some examples can be found under the heading Quote from a work citing another author on this page- https://www.lib.uts.edu.au/help/referencing/harvard-uts-referencing-guide/more-information#quotations

Hope this helps, let me know if not

David

david.litting@uts.edu.au