I told Sally how to get here, but perhaps I for her.
A. had to write it out
B. must have written it out
C. should have written it out
D. ought to write it out
网友回答
A. had to write it out
B. must have written it out
(答案→)C. should have written it out
D. ought to write it out
解析：考查情态动词+have done的用法：句意是：“我告诉过Sally 怎么去这里，但是也许我应该给她写出来”，可知说话人现在觉得自己当时应该把地址写给sally，而事实上没有，should have done就表示“本应该作某事而没有做”，是一种虚拟语气的表达，符合题意，其它项：A 表示“不得不”，B表示“一定写过了”。D不表示过去的状态（表示现在或将来应该写出来，选C。