The phrase "a time when cooperation" is correct and usable in written English.
It can be used to refer to a specific period or instance characterized by collaborative efforts or teamwork.
Example: "The project was successful because it was a time when cooperation among team members was at its peak."
Alternatives: "an era of collaboration" or "a period of teamwork".
First, the US withdrawal creates a transatlantic divide at a time when cooperation between Washington and its European allies is critical.
The fate of the proposal hangs, for the moment, on the cooperation of the imams of those mosques — at a time when cooperation with the police is a delicate matter in New York's Muslim community.
"Failure to renew that would sever our economic ties," he said, "denying us the benefits of China's growth, endangering the strategic partnership, turning our back on the world's largest nation at a time when cooperation for peace and stability is more important and more productive than ever".
The researchers speculate that their finding may hearken back to a time when cooperation between males conferred a survival advantage.
Relations with the bloc's powerful Eurasian neighbor, which has long sought to become the first majority-Muslim country to join the union, have sunk to a new low at a time when cooperation has never been more critical.
Many member states took these obligations seriously at a time when international cooperation against al-Qaida was strong.
Ed Miliband, leader of the Labour opposition, said Mr. Cameron had isolated Britain, a dangerous move at a time when European cooperation was essential.
"A retreat from globalisation and multilateralism is a serious risk at a time when international cooperation and coordination are as critical as ever".
It would also drive a wedge between the United States and its strategic partner, Turkey, at a time when regional cooperation is so valuable.
So Whitehall's move - and Gordon Brown's bellicose tone - smack of unnecessary British unilateralism at a time when international cooperation is vital.
Tim Wright, the Asia-Pacific director of the International Campaign to Abolish Nuclear Weapons, said Australia was turning its back on the UN at a time when multilateral cooperation was more important than ever.
