Gil"We found the solution even on that toughest of issues," the U.S. trade official told Reuters in a briefing on a tentative deal struck over the weekend in Tokyo on the proposed Anti-Counterfeiting Trade Agreement.
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What is the meaning of "that toughest of issues" here? The Anti-Counterfeting Trade Agreement was the most difficult item (issue).
Can I replace the bold phrase by "even on that toughest issues"? No. The Agreement was only one issue. The plural form would be - Even on those toughest issues.
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