The phrase "is firstly that" is correct and can be used in written English.
It is commonly used to introduce the first point or idea in a series or list. Example: "The main argument in favor of increased government spending is firstly that it can stimulate the economy and create jobs."
What makes Pokémon GO so special is firstly that, well, it's Pokémon.
The message to the public is firstly that the risk to the general population is low.
The short story told by the figures is, firstly, that increasing numbers of frequent Tube and bus users alike have also been getting around by bicycle and, secondly, that the rise has been greater among Tube-travellers.
Let's face it, the real problem with Costa is firstly that he stopped scoring goals eight months ago; and secondly that he has now also stopped resembling anything like a high-class central striker.
There is, firstly, that Glee problem of performers who look of an age where they should be shopping for Cath Kidston towels rather than seen wearing baseball caps backwards in public.
The most shocking thing for me returning to the book as a parent is firstly that they really are as horrific as I remembered, but worse than that is that Hoffman wrote it as a Christmas present for his three-year-old son.
"The motive behind this seems to be firstly that Robin Williams wanted to make sure his image isn't tarnished, with unauthorised images used in adverts for example or films, which technology has now made possible.
These are, firstly, that the prosecution of the war, especially in its last weeks, has been unnecessarily brutal and careless of civilian life, perhaps even breaking international humanitarian law.
The explanations given for the reduction in the number of SCRs are, firstly, that local agencies are now reluctant to have SCRs undertaken because they do not want public exposure of their failings through the publication of unedited full reports and, secondly, that they do not want to incur the cost of doing SCRs.
Angela Knight, chief executive designate of the British Bankers Associationn, told the Guardian: "Where we have questions are firstly that when regulators look at issues they need to look at the [wider] issue and not take narrow views and secondly that they need to think about consequences".
"Normally you've got a subsidiary, so you can nearly always go through the courts of the local place where it all took place,' says Day. "The problems are firstly that you have to find the costs, secondly the process will take many years and third is corruption".
