The phrase "alone demonstrates" is correct and usable in written English.
It can be used to indicate that something by itself is sufficient to show or prove a point or idea.
Example: "The data alone demonstrates the effectiveness of the new strategy in increasing sales."
Alternatives: "by itself shows" or "solely proves".
That alone demonstrates how much the law needs to be changed.
That alone demonstrates that we need a rigorous, fact-driven assessment of bioweapons threats, both from other counties and from terrorists, domestic and foreign.
"This rule alone demonstrates that the designers of the commissions intend to exercise central control of the process without interference by independent checks and balances," Major Mori said.
These improvements are incremental compared with PET, which alone demonstrates high levels of sensitivity and specificity for a wide range of disease states.
In the version of the story found in the Annals (1.4), Confucius is one-upped by Laozi, who alone demonstrates the highest level of impartiality.
Cdr Stephen Watson, from the Met Police, said: "The fact that there were over 2,000 fewer victims of crime on the bus network during the last 12 months alone demonstrates the importance and the effectiveness of our work".
Two million people in London alone demonstrated against the war on February 15 2003.
As the headlines this week alone demonstrate, the whole process of determining drug classification has become quite complex and highly politicised.
And yet that is Scheuer's claim — one he fails to back up, let alone demonstrate conclusively.
Just knowing what the interviewers are looking for, let alone demonstrating your strengths concisely while under pressure, is incredibly difficult and requires careful planning.
"However, the record does not support that such disappointment and frustration standing alone demonstrate a basis for the exercise of sound business judgment".
