If I ______ the project deadline, I would have conducted more quality checks.
答案解析
核心考点：虚拟语气（过去事实相反） 解题思路：主句用would have done结构，条件句需用had done 选项分析：C正确（过去完成式）；A/B时态错误；D现在完成式错误 易错点：虚拟语气中主从句时态配合规则
正确答案：C