The phrase "mainly wrong" is correct and can be used in written English.
It typically means that the majority or most significant part of a sentence is incorrect or inaccurate. Example: "Although her essay was well-written, the conclusion was mainly wrong as it failed to address the main argument of the paper."
Now, with the White House mired in scandal and Mr Gingrich weakened, Mr Gephardt has bounced back.Yet the Gephardt triumph is depressing, and not only because his policies are mainly wrong.
In conclusion, since the computer models all failed and since the experts were mainly wrong, there seems little for us to rely on as investors other than closing our eyes, going with what we feel is right, and hoping that we're Luke Skywalker and our last missile blows up the Death Star.
In the C-U, the minor MPEs were mainly wrong pharmaceutical form errors and infusion rate errors.
This is not to make any comment on the rights and wrongs (mainly wrongs: everyone, everything is wrong here) of the ECB's treatment of one of England's greatest modern batsmen, a transcendental kind of cricketer whose best innings were beyond the reach of most and who has a well-earned reserve of wider public affection as a splash of colour in often grey times.
The rest, Scruton diagnoses mainly as wrong though very clever, or wrong and not very clever, or just shatteringly boring.
European phone deregulation was around the corner, and Telefonica, known mainly for wrong numbers and months of waiting to get a phone, was scrambling to shape up.
It is ghastly, but mainly for the wrong reasons.
Until then, he's mainly just usefully wrong.
Most of the commentators, again, seemed to get it wrong, mainly because they were grading on a curve.
But most troubling, most scary, was the simple assertion that "compassion is wrong", mainly because it can resonate, with such a lazy and an easy chime, with otherwise diffident, right-thinking people.
"The current abysmal situation of the world and the bitter incidents of history are due mainly to the wrong management of the world, and the self-proclaimed centers of power who have entrusted themselves to the devil," Mr. Ahmadinejad said.
