The phrase "adding that the toughest" is not complete and lacks context, but it is grammatically correct and can be used in written English when followed by additional information.
You can use it when you want to introduce a statement that elaborates on a previous point, particularly in discussions about challenges or difficulties.
Example: "The team faced many challenges, adding that the toughest obstacle was the lack of resources."
Alternatives: "noting that the hardest" or "mentioning that the most difficult".
Sutton added, "That is the toughest thing in the world to do".
Torbor added that the toughest aspects of kickoff coverage were bouncing off blocks and not running out of position, which creates holes.
He added that the tough measures were aimed at ensuring Greek wage stability in the future, including for low-income wage earners.
Lyons added that the tough stance adopted to Lehman's by the US treasury had encouraged John Thain, the chief executive of Merrill Lynch, to accept the takeover offer from Bank of America.
"Talk is not going to change the situation," he said, adding that the he believed the tougher tone was largely for the benefit of the U.S. domestic audience.
By 2015, Sir Merrick said, local government would have had to make £20bn in savings, adding that the next two years would be "the toughest yet" for those reliant on council services.
Speaking on behalf of France as well as Britain and Germany, the French ambassador to the agency, François-Xavier Deniau, said, "We're disappointed that cooperation by Iran is only partial and reactive," adding that the Security Council should consider tougher sanctions.
"I've always been a big proponent that you don't need to make courses long to make them tough," Donald said, adding that the U.S. Golf Association "will make Merion plenty tough for us.
"We're navigating a difficult period with patent expiration," said Lowth, adding that the next two quarters would be even tougher.
"Minicabster was part of a sale process, which completed recently," he told TechCrunch in a statement, adding that the minicab market is becoming "exceedingly tough with the increased costs towards customer acquisition" and the challenges faced by minicab operators in retaining quality drivers.
