Is there an meaning of '[[]]' in a list?

Mon Nov 23 03:57:36 EST 2015

Quivis wrote:
> On 2015年11月19日 12:40:17 +0100, Peter Otten wrote:
>>> those questions that are a little harder
>> And just how is he going to determine what is hard?

Note that I said "a little harder", not "hard".
Write down your next ten or so questions, then work through the tutorial or 
another introductory text, then use a search engine, then post the one or 
two questions that are still unanswered.