The part of the sentence "let alone concentrate" is correct and usable in written English.
You can use it when you want to emphasize that something is even more difficult than a previous idea. For example, "Trying to find a job in this economy is hard enough, let alone concentrate on finding one that pays well."
It certainly requires substantial effort simply to concentrate on, let alone enjoy, the abstractions of Stockhausen's stark "Kreuzspiel" ("Cross-Play"), whose title refers to exchanges among oboe, clarinet, piano and percussion.
In fact, senior administration officials find it hard to imagine that Mr. Putin would step aside and leave the trappings of office to a successor, even a weakened one, let alone the power he has concentrated in the presidency.
To start to build up sales in a city where very few people knew what a macaron was, let alone have tried one, Ms Dhingra concentrated on giving away free samples.
The Devils have four potent forward lines that make it difficult for opponents to concentrate on stopping any of them — let alone their top line of left wing Zach Parise, center Travis Zajac and Langenbrunner.
The idea of sitting still for longer than was strictly necessary, let alone for the length of time required to concentrate on a book seemed ridiculous.
Wealth will concentrate to levels incompatible with democracy, let alone social justice.
Didn't they know that I was essentially out of my mind and couldn't concentrate enough to write a grocery list, let alone a new ending?
Mr. Long could not yet walk, let alone run, but the correspondence encouraged him to circumvent depression by concentrating on getting back to competing.
Wright is highly unlikely to help them before the All-Star break; Alderson said Wright needed to concentrate on loosening his trunk muscles before he took batting practice, let alone played in a game.
Little research concentrates on the effect of different dimensions of face on consumer behavior, let alone variant effects on ecological product consumption.
