“机会之窗”常见的英文表达是 “window of opportunity” 。
例句：
We must seize this window of opportunity to expand our business into new markets.（我们必须抓住这个机会之窗，将业务拓展到新市场。）
The current political situation offers a window of opportunity for diplomatic negotiations.（当前的政治局势为外交谈判提供了一个机会之窗 。）