单选题 The student asked her professor if he would have gone on the space ship he did know earlier.
【正确答案】 D
【答案解析】虚拟语气。本句是对过去事实的假设，条件从句的谓语应用过去完成时(had known)，而if条件句中如有were，should，had，可将if省去，而把were，should，had放在句首。因此选项D是答案。