The phrase "alone supports" is correct and usable in written English.
It can be used to indicate that something is the sole source of support for a particular idea, argument, or situation.
Example: "In this debate, the evidence presented alone supports the conclusion that climate change is a pressing issue."
Alternatives: "solely supports" or "only supports".
In terms of her being a single mother, whose salary alone supports her family, that's very typical of the people we serve".
It is estimated that the Great Barrier Reef alone supports a tourism market worth more than A$1.5bn£842m2m) a year to the Australian economy.
Although they hold differing views on abortion and capital punishment -- Ms. Allen alone supports abortion rights and opposes the death penalty -- they chose to play down those issues during the debate, which mostly focused on terrorism, the Middle East, Mr. Torricelli and the arcane matters of taxation, debt service and bond ratings.
Almost no one today defends what came to be called the Natural Law tradition, yet it alone supports the "self-evident truths" proclaimed in the American Declaration of Independence, or the affirmation in the French Declaration of the Rights of Man that men are born free, or the rights proclaimed in the 1948 Universal Declaration of Human Rights and those in the European Convention on Human Rights.
I don't believe this number alone supports such conclusions.
Lateral plating alone supports the medial column indirectly and allows for a greater stress concentration on that side.
(Let alone supporting policies that would help working parents).
Grace Mugabe has little public support, let alone support from the real kingmakers: the security apparatus.
Standing alone, supported by so many, she delivered the last word on her greatness.
I do not believe Australians would welcome, let alone support, another republic referendum during her reign.
Few people in India have even heard of their village, let alone support their protest.
