はともかく・はおろか・はさておき・はさておいて: the difference
Setting aside, Apart from
Tested once in past papers
冗談はともかく、そろそろビジネスの話をしよう。
All jokes aside, let's get down to business.
Let alone, Much less, Needless to say, Not to mention, Not only but also
「ルームメイトはオムライスはおろか、おにぎりさえ作れない。」
'My roommate cannot even make onigiri, let alone omurice.'
(Leaving or putting) aside, Apart
それはさておき、会議の本題に移りましょう。
Putting that aside, let's move on to the main topic of the meeting.
How to tell them apart
「はさておき」: deliberately changes the subject, putting the first aside and moving to what should be discussed now.
「はともかく」: compares two things; ignores the first even if it has problems and stresses that the second is better or must not be compromised, as in 「値段はともかく、味が最高だ」 (Never mind the price, the taste is the best).
「はおろか」: an extreme contrast, 'not even A, let alone B'; it does not change the topic.