"that they therefore" is correct and usable in written English.
You can use it to connect two ideas, with the first idea leading to the conclusion presented in the second idea. For example: The students had worked hard all year, and their efforts were rewarded with excellent grades; that they therefore decided to celebrate was unsurprising.
He accepts that his actions broke the licensing agreement and that they therefore had the right to shut his show down.
"We've written to the Home Office and we've asked that they therefore issue the police with new guidance, but we've heard nothing back," says O'Brien.
The Judge pointed out that Mr. Culbertson had no evidence of the existence of these people and that they therefore could not be discussed.
"They are going to be assuming more risk," she said, pointing out that they therefore need to reduce their financial risks.
Finally, we argue that the fault injection and monitoring mechanisms required to run such benchmarks are reusable for online robustness testing, problem detection, and problem diagnosis, and that they therefore should be provided as infrastructure services.
"To the outside world, it might have appeared that they therefore were relatively well-heeled, but they were, of course, heavily indebted to the bank and their financial position began to worsen considerably over the next two years," Robertson said.
So it's on the men to appreciate and realize they have that, and therefore when they look at women they can realize that they have to give that relationship a little bit more time to develop.
We see people shooting partridges; we see their beaters – and without any indication that they are therefore snobs.
He argued that they were therefore a prism through which social changes were magnified and reflected.
But he cautions against concluding that they are therefore no longer worth teaching.
Some HP shareholders may conclude that they should therefore back the deal anyway.
