4. If you ----- faster, we could have turned in the project

虚拟语气 应该是had worked
②表示与过去事实相反的情况
从句谓语动词形式 主句谓语动词形式
had+过去分词（过去完成时） should/would/could/might+have+过去分词（现在完成将来时）（过去将来完成时）
eg.If I had got there earlier,I should/could have met her.如果我早到那儿,我就会见到她.（事实：去晚了）