"I would be extremely grateful if you would do it" 或 "I would greatly appreciate it if you would do it" 是表达感激的常用说法。
来源: 这是一种常用的、正式的、礼貌的说法，它可以在多种场合中使用，如请求帮助、表示感谢等。
例句1: "I would be extremely grateful if you could help me with my project." (如果你能帮我完成我的项目我会非常感激。)
例句2: "I would greatly appreciate it if you could give me a hand with this task." (如果你能帮我完成这项任务我会非常感谢。)